It’s a console-like device for people who want the full PC gaming experience without the large PC form factor. It comes with Steam OS preinstalled and 1080p60 on medium settings should be fine for the people who play on the couch with the large TV two to three meters away.
But I guess, it’s mainly sold to tiny form factor fetishists because it’s definitely not cheap, and you probably can just slap Steam OS on a used gaming PC.