I love and support this idea very much. I had actually been thinking about this exact solution myself, but I'd personally want to stay clear of anything involving real money, so it's great that you're doing it. :)

Just a note which probably isn't worth your time to act on, but using this service as a maintainer in Finland is illegal unless you can offer a geoblocking feature that can block any Finnish supporters from routing money to Finnish maintainers. This is due to our Money Collection Act which prohibits soliciting any donations except for very strict circumstances which aren't really applicable here. Might be worth a note on the page if you have extra time, since this is not know by many Finns that I've talked to.