The problem is their ubiquity for payments (manageable on its own, though some sites only take PayPal),

AND the most reliable/usable p2p micropayments UX for non-technical people and international, under one umbrella. Yes there's crypto but good luck getting your parents to use.

Unlike in Europe and elsewhere, Americans don't have good (and somewhat standardized UX for) direct payments from bank (e-check sucks), or bank-to-bank. And you'd never want to use wire ($18+) for paying friend back for pizza.

What does it leave? CashApp, Zelle, etc. ? And Wise for international. They only address a subset of the latter use case.

> And you'd never want to use wire ($18+) for paying friend back for pizza

Sending and receiving wire transfers is free with my bank, but even still no way I’d ever use it for that use case.

> some sites only take PayPal

Wow, really? Never have actually encountered a site like that. So I can only assume it's rare enough such that it wouldn't be much of a hassle to just refuse to do purchase things from those websites.

Manning online bookstore. In theory they support credit card payments, but I guess they are not capable of handling 3D Secure protocol, so my attempt to pay with a credit card always fail with them. Every time I need to buy something from them I would create a temporary PayPal account (which I delete after the transaction :)