Android games are normally going to be inferior to Steam games, but this is still a nice option for games that aren’t available on Steam or can’t be played due to anti-cheat reasons.
You can read more about Waydroid here. There are reasons to believe valve is working on adding official Waydroid support to Deck, but until then you can install it this way.
I would prefer the official YouTube client and web browsers properly developed for touch to be available in game mode. The best touch browser is currently Angelfish and that’s not a robust browser.