I'm just going to mention real quick that 90% of your users are from modpacks, if you REALLY want to go with the "I want money, everything is to be paid now", not only will every modpacks yeet your mod out of existence, but you'll also get very little money. Replacement mods exists. I for one wouldn't feel at ease to give my credit card information to some random russian (specially from world of tanks) on the internet and I'm not the only one to think like that.
tl;dr you're shooting yourself in the foot and you don't even have the foresight to see it happen.