He can only repel or attract base on what's positive and negative. Which means he has to touch something and make it positive while also touching something else and making it negative. The reason why metal is so easy is because metal is already magnetic. So there is zero need for him to make metal magnetic. Now his awakening allows him to magnetize things which means ita going to take alot of setup or prep for him to use it since he now has to manually magnetize things onto something