Steam Deck is equivalent in power to a PS4 and its battery goes down quickly if you run anything AAA. It's also a Linux machine, so anyone wanting to get emulation and other computer specific features setup in Desktop Mode will have to learn to use the terminal, which is just not a user friendly experience for the casual player.
I own a Steam Deck. Love it even. But your average person is not going to find it to be a suitable replacement for the simplicity of a console. It also still has all of the same problems in terms of worrying about specs and fiddling with the setting