score:4
If you are interested in both United Club membership and holding a United mileage credit card, by all means go for the United Club card. But everyone isn't necessarily like you.
All the U.S. carriers are heavily dependent on their affiliated credit cards for revenue, so it is unsurprising that United finds the idea of gaining another cardholder more desirable than a mere hundred dollars of annual revenue. The time may come when that is no longer the case, and the annual card fee and the annual club membership fee may fall closer together in price, but the option to join the club without holding the credit card is not likely to go away.
(Note that the United Club membership provided through the card is a regular United Club membership. There is no special tier of membership just for credit card holders; you are not entitled to any benefits beyond an ordinary Club membership. You are entitled to same number of guests as well: 2 adults, or 1 adult with any dependent children, not an unlimited number of traveling companions.)
Upvote:3
Firstly note that United Club membership also allows up to 2 guests - same as the United Club Card. The higher 'plus Spouse' rate means that you both get a card, and thus can both enter when travelling separately. The price you've stated is also only correct for someone without any status in United's Mileage Plus program - the higher your status, the lower the price. (eg, as a 1K, my UC membership only costs $400/year)
In general, the only different between the two methods of access is that the United Club Card is a credit card, and thus requires you to apply for it, and sustain the impact that such an application will have on your credit score. Obviously if your credit score isn't high enough it's also possible that you'll be rejected.
United Club membership on the other hand is just a simple payment. No impact on credit score, no chance of being rejected, etc.