Which is 99.9% of the users and probably not a blocker for main stream adoption especially if it’s not the only way to pay (Bank transfer, cash etc all still works).
It’s not a blocker for adoption, but it is a serious problem.
It really isn't. It's the definition of an edge case.
Edge case or not, I do consider a dependency on user-hostile proprietary software owned and controlled by foreign companies a serious problem by nature. Most people not caring doesn’t make it any better.
By that logic we can close Serbian schools in Romania.