The advantage seems to be that you don't have to worry about the details and you get updating for free. Writing good update code is hard and thankless, but you can certainly do it yourself.

Not a tonne of benefits, but not a tonne of costs either. I'm sure Samsung won't use this, but this might be good for projects just getting off the ground.

some are: access to media frameworks, there are more android app devs and resources out there compared to whatever linux GUI framework you might use.