No one is backing them. Users don't care about how crypto works they care if the product works. Take applepay for example, majority of merchants use it because users want to pay with it. Users don't care about a lecture on privacy and government overreach. Tell them it does 2 tap/click payment and also it manages your cc and then give merchants free crypto payment terminals. You can onlh use it online and only if the site owner cares enough.

Tell site owners "here is a service that manages all payments including a ton kf crypto and converts it to uour local currency, also, users can sign up with us and use as an idp so they don't have to register on your site" .

In other words, an Oauth2 extension for payment processing providers + federated identity and services that provide easy integration into your registration+payment workflow might be lacking. Also, with any crypto it is a PITA to just obtain crypto without KYC laws, so more accessible exchanges that are somewhat anonymous without needing Tor that let you barter cash or other payment with them (not other users, it's a mess) might help too.