They are kinda fun.There really is no point in them though.You can only use hats on Streetpass Mii Plaza and not some big games like Mario Kart,which USE the feature but don't showcase the accesories,which is the whole point in Streetpass Mii Plaza.But I did hear that if you collect all of them then something good happens...
eh probably a myth. :/
eh probably a myth. :/