This is just talking about games approved through Valve's verification process. There are a lot of games that work that are "unverified", not to mention the entire history of gaming available through emulation.
I like the Deck, but lately been using my Switch again because I like the battery life and the smaller form factor sometimes. I hope Valve releases a Deck that is a little easier to slip into a bag and that can do a bit better than 1.5-2.5 hours of battery life.
I’ll still use my Deck, but in some cases where the same game I want is available on Switch and I am traveling, I will choose the Switch for its form factor.