Well the Devs loose sales, since people from specific Regions can´t buy their Games on Steam anymore. Especially not titles aimed at adult audiences or too old to be having a rating ones. That´s why they need alternatives like Itch.io to sell them to us still, since only Steam agreed to some nonsense that locks away these titles since 2020 in Germany and Brazil.
Also adult Gamers get treated like kids by Steam now since they refuse to add a proper age verification. So its sad i can only see Demos of many Otomegames here and not purchase them here instead, where they aren´t an issue. So only seelling on Steam will leave out big parts of the Gaming community who will glaldy purchase them via GoG or here...it´s not like Steam is the only way to buy PC Games from.