Being on more platforms is always better unless it’s a hassle to support or get there.
itch.io in particular is a very nice platform allowing you to put all kind of (DRM-free) stuff on it, even the smallest game, also free games or prices with open end (e.g >= $5) (or ebooks).
This platform allows you to select the amount of money which goes to them (vs. fixed rate of similar platforms, like 30% on Steam/GOG).
Somehow a lot of people just don’t care, I don’t know.