Depends. As
>>20695249 pointed out the Fairy hype's gonna get GF some quick and easy money for a year or two, so from that perspective it definitely didn't do harm.
From a competitive perspective it's a slight improvement in the short run but in the long run it's just going to become another OP type that GF will need to nerf, because Fairy has one of the best type match ups in the game. It's an amazing example of GF's incompetence when it comes to game balance, since they were specifically trying to improve things but fucked up.
Though on a personal note, I love the flavor of the type as I'm a fan of both cutemons and mystical mons, so it's pretty win-win for me.