"superpower" is overstating it. Picking up paperclips is neat and being able to feel metal detectors as you walk through them or tell if things are ferrous is also fun but it's more of just a "power" than a superpower. It also has the downside of you needing to be careful around hard-drives and other strong magnets. On net I'm happy I got them but it's not amazing.
FYI, there's no need to be careful around hard drives (except for your own safety, since they're large chunks of metal your magnet will stick to.) The platters of a modern hard drive are too high-coercivity and too well-shielded for even a substantial neodymium magnet (bigger than you can fit in a fingertip) to affect them.
Credit cards, on the other hand.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.