Windows is ok on my desktop PC (even though I’m thinking of going Linux the next time I upgrade it), but it’s not very pleasant on handheld devices.
The Steam OS was created the way you can use it similar to PS or Xbox console. It’s focused on simply accessing and playing your games, with great UI, full controller support and no unnecessary bloat. You still have a desktop mode to use the device as a regular PC, so the option is there.
I dont want to deal with all the windows stuff on my handheld console, I just want to play games.