if steam has a console it will probably just be a baby's first gaming PC with a super simplified OS that will probably just only run steam and play all steam games. I am not expecting anything innovative if they actually do make a console, we'll see though.
consoles that play pc games is good.its how it should have bee since the early 90s
Turning it on is probably going to be like launching Steam. That will be the console's dashboard. It's supposed to have hardware that developers can develop games around, so you won't need to upgrade it ever 3-4 years, it will no doubt run Steam games. It seems like it is a more portable PC that you can connect to your TV, and simplified PC.
You should have to rotate a valve on the front to turn it on.