No, it's definitely not better than Steam, but it is much cheaper and more user-friendly in the VR world. It's also the only app that Oculus Quest can natively attach to since, in order to get Steam on your Oculus Quest, you will need to attach it to your PC via another app. The library of Steam is far superior, though, and the best titles you can play on VR are generally located on Steam. Sidequest has a lot of great games, too, though, and they usually come in the free variety, so that will appeal to many players just the same.