You’re right, I don’t, but it sure as hell makes it a lot easier to keep the hundreds of games that I have purchased organized. Not to mention I don’t have to manually keep each of the 95 games I currently have installed updated or have to worry about backing up game saves or having them available across multiple different devices with zero effort from myself.
Steam isn’t perfect, but it does add a massive amount of value for consumers like myself who take advantage of a lot of the different features that are mostly unique to Steam as a platform.
Also, I believe when a developer releases a game on Steam they are given the opportunity to use Steamworks, which provides a lot of potentially useful tools for a game deceloper.
I always wonder if maybe the devs are wanting an out from finishing the project but still want the cred for working on it. So they make the announcement fully knowing Nintendo will come down on them which will then alleviate them from having to complete the project.