I bought a switch 2 over a steam deck. I have over a thousand steam games. A few reasons:

Nintendo makes fun games that I want to play. I want to play the new Metroid, the new Pokémon games, Kirby DLC, etc. Maybe it's nostalgia, but I grew up with the original Metroid, and that series sticks with me.

The switch 1 gets a ton of use in my house. Switch 1 games perform so much better on the 2.

The pro controller for the switch 2 is incredible.

Switch 2 is cheaper, significantly cheaper if you play docked. Our family uses it to play docked a lot.

The switch 2 library is large enough that you can play a lot of the same titles you can on the deck. Or at least enough games you'll never run out of fun options. You don't need to have the biggest library to be fun.

I have a powerful PC in my house for when I want to play shooters and 4x games. The switch 2 library gets way more exercise.