Well no they don't have to be scoring, it would be sensible to take some scoring units in an unbound list but doesn't mean you have to, but this all comes down to objectives. I can see unbound being amazing for tyranids and harlequin lists, I can see so many crazy fun lists with unbound, how about a nothing but one aspect army list. What about a terminator first company led by Lysander. Or the devastate or assault companies? Tank company or air Bourne AM, you could even arrange massive dogfights where you only use flyers.

Everyone has jumped on the anti fun band wagon but these are just a few of the ideas, yes it's open to cheese but it's also open to some crazy fun ideas!