I feel this one is as relevant as ever, given new hardware is making its way to us soon.

Currently on the Steam Deck, navigating the store is so arduous, most find themselves just purchasing games from their PC/phone then downloading the purchase once it's in their library. There's no dedicated app that allows for easy navigation using a controller, just a wrapper around a web-page with very limited controller support.

With the upcoming Steam Machine, new users are likely going to be moving over to Steam OS-based hardware and could be overwhelmed/turned off by the difficulty navigating the store. Having a controller-friendly app will not just vastly benefit user experience, but will surely help line Valve's pockets more with purchasing new games made ever-easier. It's a win-win!

(Apologies if this has already been suggested to death, I searched the active suggestions and couldn't find anything myself)