It is mostly the same game though. Nothing has been really redesigned enough to call it a new game compared to an update. It's still 95% the same art assets. It's slightly more simplified than the itch.io version mechanically aswell (Which is fine).
Personally I prefer the itch.io version. The steam version has a lot of things removed that I personally liked about the itch.io version. Minus the custom gamemode it hasn't really "added" anymore to the game. The quality of life stuff is nice though.