Quote: "Why not just buy a cheap android phone or tablet, or rasberry pi and connect that and a controller to a TV set. Whats the advantage of buying this?"
Technologically? Probably very little. But most folks aren't geeks, even console gamers - heck people don't have very much imagination

. Whilst, yes, it is possible to hook up those devices but I think the main thing here is to do with marketing. It's Android repackaged and sold as a console with all the bits and pieces set up and ready for a console user.
Arguably, the main difference is the marketing...at least as far as I can see. But opening up or expanding markets for indies should make some of us a little excited.
I suppose somebody could release a new phone and market it as console device as well and have it connect to the TV and set it up to work with a wireless controller and market it that way. Maybe a Samsung Galaxy Play or a Motorola Gmr. But I don't see them doing it, *shrugs* maybe the NGage was a bit of a deterrent and maybe the casual gamer and 'app' route is turning out to be more profitable. I guess when people think 'mobile' they think on the go. Shame, because you can get HDMI cables for mobile phones.
Arguably a person could just hook their laptop to the TV (or their desktop) PC games tend to be controller compatible and you can use tools for games that aren't. I use my laptop with my TV, even in the living room - connect to Netflix and we get decent TV for a fraction of the price for Sky. With Windows 8's tiles, it's a lot more readable from a distance as well...I would use Windows Media Centre, but it lacks a lot of services - you can't even use Netflix on it if you're not in the US.