If you want be more independent from Steam, why are you requiring Steam to be integrated? What's the point?

I'm not the original commentor, but it would be nice to have an independent interface that could just show you all the games you own in one coherent searchable interface that also lets you install and play them.

Steam only shows Steam games and the non-Steam games you have added. Heroic only supports Epic and GOG and some smaller stores. Lutris more or less does support most vendors but is clunky and doesn't offer a combined view. I think Playnite does this but is Windows only at the moment. Same with GOG Galaxy.

And if you had to ditch Steam at some point for whatever reason it would be nice to be able to continue using the same app as before.