score:2
Think of check-in as having morphed in meaning a little. Now it's more like say, committing to the flight, saying "yes I'll be there, lock it in".
Saying that, I've checked in for a flight with 45 min to go, and then with 15 min to go, realised I couldn't travel, and cancelled my check in. It just helps them with numbers.
Another factor is loading. Some flights in Australia, for example, might be an overloaded 737, and then they switch in a larger A330. Check in rates if lower than normal, give them an indication that perhaps it won't be full and a 330 isn't required. (This is hypothetical, but I've seen tails/regos change mere minutes before a flight too)
*Source - I've flown a lot this year for work, contracting at an airline.
Upvote:-1
It's a good question.
The answer is that "check-in" simply no longer means what you accurately point out it literally means.
We live in a marketing-driven era and language-meaning-and-logic is subjugated to catchy terms and marketing implications.
(Note that even if you do use modern "check-in", you have to, well "actually check-in" your bags if you have any. Note that they are now shifting that term to an exciting! new marketing term ... "drop-off". In the next 20 or 30 years they'll probably move "drop off!" to the thing presently called "check-in" ... and they'll have to think of another term for "literal check-in"!)
It's likely that in the future the process of {what is presently called} "check-in" will just be eliminated: when you "buy a ticket", the airline will at that point just build in the process where they (incredibly) try to charge you more for a seat, and you have to eula security questions, etc, i.e. the process that is currently presented as "check-in".