We are currently adding credit card payments to the OpenCivics GG 21 round. It works by people sending fiat to us through PayPal and then we send crypto from a wallet generated for them into the Gitcoin projects. The proof of personhood consists of legal names that we obtain from PayPal in order to give them matching. This means to use Gitcoin and donate and receive matching, a non-crypto person can easily donate in a familiar way. 
We will share the results in writing and are likely presenting about this at DevCon. 
See this (not yet public) demo showing some of how this works: https://youtu.be/19LFDAIDsB0 