The problem is there is still a significant price to use it.
Fair enough the monthly sub isn't bad but pricing the Chromecast + controller at £119 when an Xbox one can be had (with controller) for £20 more?
I could look at using that £20 to spend towards a game and be playing pretty much instantly, whereas you’d have to set up the console, download any updates, then buy a game (physical or digital-whatever your preference), then wait for the game to install, etc..
£119 is a bargain if you ask me.