They're good for classes without martial proficiency especially depending on how good the magic weapons are in game.
Also wolfheart said there are some race restricted magic weapons so there might be some sort of special human only necromancy scythe or something.
Polearms are DEX based weapons so the proficiency is a waste if you don't plan to play a class that has high DEX. Now this is fine, every race has always been better geared towards specific builds if you want to optimize. But the sacrifice seems far smaller than it's ever been if you want to pick a race not properly suited for your desired class than ever before. And I think this is what WotC are deliberately aiming at...they want to reduce race to a mostly cosmetic choice with minimal differences that only min-max players will sweat over.
