It's interesting that I'm at the point where people ask me to add optional payment methods to a free game. :D
My biggest problem with it was that "$0 or more" sounds as if it will scare off some people that don't want to select $0 even if it is available and thus lowering the player base. I also need to check the payment and tax systems of itch.io first to know if I can even use it.
Btw, it's possible to make a pledge on patreon and cancel it immediately, so it doesn't need to be a continuous payment. ;)
I'm always happy to hear people enjoy the game so much. <3