I see your point but I also see the potential hassle to keep such a wiki up to date. Most of the informations are the same for all countries, always, like how Revolut withdraws money from different wallets depending on local currencies, base currencies, et cetera. And other things are local, like ATM fees or how the card works with public transport in in London. And its difficult: In the US, for example, ATMs in rural areas might not have a surcharge, while ATMs form the same bank in Manhattan have. Last time I checked, most major banks in Manhattan agreed on 3 USD fee, while ATMs at other places where free.
Another example: I remember a discussion here in this forum about the ticket machines for New York subway: the machine might ask for a ZIP code. People reported it worked without entering one. Other people said, 00000 did the trick. While others said that didn’t work, they entered 99999. (I myself was able to buy tickets without entering a ZIP.) What‘s that about? Different types of machines? Is it because of different card issuers with Revolut? Did the company in New York change their machine programming?
Or car rentals. Avis has a general rule not to accept prepaid cards, as far as I know. But if users are able to convince the guy behind the counter, it does work if there are sufficient funds for the security deposit on the card if the Avis guy uses an online terminal. Such a deposit can be surprisingly high depending on the car and on the tariff (lower deposit if the tariff already covers damages via insurance for example). I can see that car rentals would be a topic of interest for many customers traveling to the US, but it’s really difficult to generalize and give simple advice. Its kind of an endless list of “it depends”.
When new Revolut users ask basic things I often like to refer them to the FAQs and I recommend to read them fully. Because Revolut is in many ways different than the card people are used to. And I think it helps if people have read what to do in case one looses a phone on a trip before going on that trip since Revolut is a mobile only product for now. (And some seemed surprised that its linked to a phone number.) And I think the FAQs contain many informations people would not have thought about. Myself included, of course.
So I would find a more comprehensive wiki style database useful, of course. But I can see the potential hassle to keep this up do date, and to cover all the different problems people run into that are sometimes general, and sometimes very specific. And I can see the anger of users when they get very specific informations and then it does not work like mentioned because a merchant changed sth. or Citibank introduced a surcharge in San Francisco in the meantime. And lots of situations aren’t specific to Revolut, they happen with cards from other issuers as well.
(Sorry for this long opinion piece. I hope you enjoy your card in the US like I did. But I also would never travel to any place and rely only on one card.)