It's only temporary drain, the loss isn't instant, and it also makes him the meta equivalent of a lightning rod. It also onky effects a certain area, 5 meters at most, the surface of his skin at the least. He can also reverse the flow so that he expels Meta energy from the area. Gives him an advantage over energy type elemental, not so much for metas like your concrete lady. Other than that, he's completely vulnerable to all the things normal people are weak to.