I was just searching for some infos and found your question, which isn't answered as it seems.

There are only 10 Names, because these are the names of the Firstborn.

Adam being the first king of the Earth, as appointed by the Creator, handed down his right to the "Throne of Elohim" (literally that's what the throne of King David is later called) from the first born to the first born.

First Born 01 = Adam First Born 10 = Noah First Born 20 = Abraham First Born 21 = Isaac >>>> rejected 1st = Ismael >> Arab Nations First Born 22 = Jakob / Israel >>>> rejected 1st = Esau >> covenant with Ismael First Born 23 = Judah (Ruben, Simeon, Levi out because of sin) = House of Judah First Born 24 = Ephraim = House of Israel, lost sheep, Genesis 48 + Romans 11:25

From Adam to Ephraim = 24 elders before the throne of God in Heaven (Revelation)

Second Adam = Elohim's Monogenes (the only begotten son) = Jesus / Jeshua 1 Corinthians 15 / Zacharia 4

Romans 4:1 Abraham is your father by the flesh Romans 4:13 Abraham is the heir of the earth Galatians 3:29 : If you are in Christ.. you ARE Abrahams seed (hebrew sera = Sarah = I'sera'el / greek sperma ) and heir.

John 11:54 Jesus therefore walked no more openly among the Jews; but went thence unto a country near to the wilderness, into a city called Ephraim, and there continued with his disciples.

I think this is because this would eventually be the line that the Messiah would come from. If you follow the list down you see Abraham, Isaac, Jacob, Jesse, David, Solomon, and so on. Matthew chapter 1

It could be that those 10 where then important to the bibles message. I don't think they where more important than others, except in the scriptures where they had a role to play. It would have taken up too much space in the bible and would have been a tangent to it's message. The names may have been recorded somewhere else and lost in time, but to the bibles message those people where not relevant.

The simplest answer is that ten names were listed because:

a) Since Noah found favor with God and he and his wife and children are the only people to survive the flood, he was worthy of mention.

b) The other people named constitute ALL of his direct male ancestors back to the creation, with NO GAPS.

See https://answersingenesis.org/bible-timeline/genealogy/gaps-in-the-genesis-genealogies/ for a refutation of many arguments in favor of assuming there are gaps in the genealogies. It includes linguistic evidence from the Greek and Hebrew. One piece of the argument I will quote:

1. There are no missing generations between Adam and Seth, since Seth is a direct replacement for Abel, whom Cain murdered (Genesis 4:25).
2. There are no missing generations between Seth and Enosh, since Seth named him (Genesis 4:25).
3. Jude says Enoch was the seventh from Adam (Jude 14), so there are no missing generations between Adam and Enoch.
4. Lamech named Noah, so there are no missing generations there (Genesis 5:29).
5. Some Hebrew scholars believe that the name Methuselah means “when he dies it is sent,” referring to the Flood. Assuming no gaps in the chronology, Methuselah died the same year the Flood began. Some Jews believed that God gave Noah time to mourn the death of Methuselah, whom they believe died a week before the Flood began (Genesis 7:4). If this is so, then no missing generations can be inserted here. If this were not the case, then this is the only place in Genesis 5 one might attempt to shoehorn the missing 22 generations! Would you trust a chronologist who was so careful to record names and ages yet omit 22 generations in his tabulation in one place? It simply doesn’t follow.

The importance of this line of reasoning is that it uses the biographical accounts found in Scripture that supplement the genealogies to rule out places where gaps of omitted names could be inserted.

Later examples of more extended lineages, as seen in Genesis 10-11 intended to show the roots of the world's present day inhabitants and, as displayed in 1 Chronicles 1-9, were also important for such things as tribal & personal inheritance rights and for priestly qualification. So, these lists would be helpful for future historical and 'legal' matters and therein received more extended treatment.

In these Genesis 5 listings, these were not issues. All of the line of Seth and their offspring, except Noah & his family, were to pass from the scene, Enoch in the most unique way. Therefore, with the perishing of those of Cain's lineage and all of Seth's lineage except Noah & his immediate family, there seems to be little need to elaborate on those whose influence ceased to exist after the Flood. The only surviving influence would be that of Noah and his descendants.

Among the observations sparsely gleaned from the Pre-Flood Era, it's interesting to note that the 'image of God' created in man was maintained and passed into the Post-Flood Era through Noah. As described in the KJV text: "Noah was a just man and perfect in his generations". If "generations" is referring Seth's Genesis 5 lineage list, this verifies that the human seed passed into the new era without corruption from demonic influence (as the apparent threat posed in Gen.6:4). So, the Genesis 5 list seems to uphold perhaps its key goal of verifying the purity of humanity that would culminate in the humanity of Christ Jesus.

It's also noteworthy to see the skill levels described in Cain's lineage (Gen.4:17-22). There is seen to be what appears a very advanced culture.

Are People Who Aren't Mentioned in the Bible Less Important?

No.

These names are recorded because they're important to the message that's being told, being our blood ancestors, (in general) righteous people, and, perhaps most importantly, the ancestors of the Jews (for whom the account was originally written) and the Messiah. That doesn't make the people who aren't mentioned unimportant in a broader sense (e.g. to God), their stories just don't have the same kind of influence on the story that God wants us to understand as it's recorded in the Bible.

Noah's Lineage

Noah was definitely a significant figure, as it was he and his family alone who survived the flood. The purpose appears to be to show Noah's lineage from Adam. Adding in brothers and sisters at each level would be a bit tangential to that purpose.

Enoch was certainly a man of note due to his close relationship with God.

The Line of Cain

Genesis 4 tells us about both Cain and Abel, who were indeed brothers of Seth. This chapter also gives us the line of Cain as follows:

Cain > Enoch > Irad > Mehujael > Methushael > Lamech.

Lamech's two wives were Adah and Zillah.

Adah bore Jabal and Jubal.

Zillah bore Tubal-cain and his sister Naamah.

So, we are actually given other names in the line of Cain in Genesis 4, even though both Cain and Lamech were murderers. The line of Noah does seem to be a more righteous line, to be sure.

The Second Gospel

There is another interesting idea that has been put forward, specifically that the meanings of the ten names in Noah's lineage have significance--sort of a Second Gospel:

Adam        Man
Seth        Appointed
Enosh       Mortal
Kenan       Sorrow
Mahalalel   The Blessed God
Jared       Shall come down
Enoch       Teaching
Methuselah  His death shall bring
Lamech      The despairing
Noah        Rest, or comfort

Put together, this could be as follows:

Man is Appointed Mortal Sorrow. [The Blessed God] [shall come down], teaching. [His death shall bring] to [the despairing], [rest (or comfort)].