Admission via credit card is solely to the United Club lounges. (The five Polaris Lounges require tickets in international Polaris Business seats.)
I am a lifetime United Club member. These clubs offer some free alcoholic beverages (house red & white wines, a mass-market beer on tap, and very basic liquors), though one has to pay for "premium" drinks.
While some people, such as myself, try to make a meal of the limited food offerings, the quantity and quality vary over the years and by location.
https:/www.flyertalk.com/forum/united-airlines-mileageplus/1949250-uc-amenities-regular-special-food-snacks-power-wifi-work.html
Within the United Airline Forum there are threads on various United Clubs, especially in UA hubs.