Ok let's make it clear lol.
Patreon artist put their stuff on gumroad because some people just don't want to pay each month. Sometime people just want one particular pack.
It's not always overpriced. Cursedmark is super cheap. Hotcha has always been super pricey and it's not only his gumroad. His patreon is 10 dollars too…
It's not pay wall or anything as these arts wasn't mean to be shared on public plateform anyway.