Valve engineer says Steam Machine performance beats 70% of PCs, and can play all games
(www.notebookcheck.net)
I mean a big difference there is that the switch can only play games that run on it. There are going to be games that don't run on the steam machine (or at least we'll), just as there aren't games that run on the steamdeck.
I think it will still do well, but that's a big difference between the switches approach to low power vs the steam machine.