Why do so many superpowered characters go into crime-fighting or crime committing? Especially when they could easily get more money, and do more good at the same time, by using their powers for other, legal purposes.
It would be hard to do with powers being handed out randomly, triggered by some metaorigin factor, but perhaps it could be influenced by personality. Still, the sort of impulsive thrill-seeker who would resort to crime for the quickness of work, or perhaps the excitement, and the sort of person who would selflessly fight crime (albeit possibly also for the thrill) are not the same type.
If the powers were handed out, it would probably need to one for the villains, and that from a nasty source, and one for the heroes, at least moderately good. Perhaps it can justify itself by saying that it is only counteracting the other source. Hmmm. . . if someone appealed to it for all the other good it could do, perhaps it will justify itself by saying the person making the appeal could be doing more good by other means, too. Still, it is going to be hard to pull off.