Because the verification system doesn’t take performance into consideration at all. It’s more of a “how much effort does it take to get the game running” indicator.

It also does not include countless games that Steam has rated as “unsupported” or “not playable” despite them working just fine.

Agreed. Also, there’s a lot of smaller 3D games that run at 30+, but end up being a bit choppy and tanks the battery life. Nowadays I just play 2D games on my Deck, then I get 3hr of battery life