Stage 2 provides physical and mental advantages over mundane humans. "Mental advantages" doesn't necessarily mean super-intelligence. What it does mean is that Stage 2 supers lack some of the mental gaps or disadvantages that mundanes have to deal with. They deal with surprise better, they have more neuroplasticity, better reaction times, and so forth.
Because of this, most Stage 2's excel in fields that depend on physical prowess or charisma, not intelligence. The people who make it into CEO positions at big companies might be brilliant thinkers, but they tend to have won their position through maneuvering and social benefits rather than some incredible invention or innovation.
So what do Stage 2's do when they aren't putting on body armor and throwing shuriken at criminals?
Businessperson. It's said that all corporations are sociopaths, and successful CEOs must be as well. Stage 2's tend to have the ultra-competence required to pull the job off without stabbing everyone around them in the back, so there's a fair number of corporate officers are Stage 2.
Diplomat. A surprising number of diplomatic appointments, especially to dangerous or unstable countries, are Stage 2. This allowed, for example, an American in Syria to rescue his staff after insurgents attacked their base a couple years ago in Syria.
Scientist. While super-intelligence isn't really a thing at Stage 2, many scientists are called on to do dangerous, grueling field work. Biologists, climatologists, chemists, and more find value in the benefits that Stage 2 provides to them. Many interesting breakthroughs have been made because a Stage 2 scientist was able to work in the right place at the right time. A few such intrepid souls have advanced to Stage 3 because of some overly dangerous encounter, of course.
Sports athlete. There are now separate competition brackets for Stage 2 athletes. Since they are officially banned from Olympic competition, and since their numbers aren't quite large enough, most of their exhibitions happen on Pay-Per-View television. These shows have gained more and more pageantry over the years, since essentially the performers are able to operate at Olympic levels more or less continuously and can take the time they'd spend training or recuperating to practice new stunts. This category also includes MMA fighters, boxers, and the like.
Television personality. The demanding schedule and requirement for telegenic speakers makes Stage 2's a logical choice when some producer needs to point a camera at someone and have them read the teleprompter while sounding natural.
Just because this part of the guide was boring to write, here's some badass music celebrating super-villains. Enjoy.