One of the dominant models of magic and superheroes is that everyone has their "thing", what I would call a bespoke magic system, but is mostly just a power that sits orthogonal to all other powers. This crops up all the time, because it's really really good for having dynamic fights, for characterizing people through their powers, for having new surprises and twists, and just generally keeping things going.
It's adaptable to all kinds of genres. Superheroes are the obvious one, whether it's canonized as Quirks or just an aspect of the setting. But I'm pretty sure that the basic concept was first invented in anime, with marital arts settings, where every character had their own jutsu or whatever, or the system in theory is all about ki manipulation or equivalent exchange but in practice everyone has their own particular niche. You can slot this into urban fantasy, giving every vampire their own special Power, or you can have some magical fantasy thing where everyone has their own unique Semblance.
So this is all well and good, but it leaves us with a narrative hole, which is progression. Having a unique power is cool, because you can think of new uses for it, have unique matchups, etc., but it doesn't give you that juicy sense of becoming more, and if you're facing down terrifying villains with their own powers, then a god-tier power is just kind of ... random. Luck of the draw, rather than the consequence of a powerful will or keen mind.
You can strip out limitations and amplify effects, and this is cool and good, or you can lean back away from uniqueness and toward uniformity, which I think is sometimes the right call, depending on your narrative needs.
So you say that actually the guy who can swap places with someone and the guy who can cut people from a distance are both unwitting hyperspecialists in the same field of magic or whatever, and that in theory, with unlimited time to train and experiment and explore, each could do what the other does.
This allows for a lot of snazzy narrative stuff. Two intense rivals "learn" each other's techniques, or at least adapt them into their own technique. Maybe the guy who does teleport swaps never learns to cut from a distance, but his teleport swap incorporates a cut into it, slashing at the person he's trading places with. A widower incorporates aspects of his dead wife's power, a mentor passes down elements of his technique to all his students, a young protagonist has some angst about using the aspect he got from his abusive father, etc.
If powers are a reflection of character, then you get to physically manifest a character's relationship with other people.
