Most people have covered it, but to elaborate a bit...

In the studio musicians are rarely playing live with the rest of the band, and even if they are playing with the rest of the band they will often be isolated in their own room. The headphones are there so they can hear the rest of the music and/or click track/whatever else they need to hear. This is done because when recording music engineers generally want to get each instrument recorded separately so they can easily manipulate whatever they want on that instrument without causing any issues for the other ones. If, for example, we had a bass and drums in the same room, if one of them made even the tiniest mistake you'd have to re-record both instruments (the bass would be heard in the drum mics, and the drums would be heard in the bass mic(s)). If the instruments are separate then you could just re-record whatever little part you needed to. This also applies to any other treatment the engineer might do, compression, EQ, pitch/timing adjustments..etc. Its basically always better to have the instruments separate for most modern recordings. Things like orchestras often record as a group because the interaction of that many instruments in a room sounds different than just playing each instrument separately and playing them back at the same time, and most classical recordings aren't going for the same level of inhuman perfection that most pop/rock/other modern genres are.

For live performances it's because of a few things, but mostly 1) stage monitors kinda suck, and 2) stages are often really loud. In ear monitors allow musicians to hear everything they need more clearly and at a significantly lower volume than without.

First, to answer your question, I use sundaras for gaming and I think they work pretty well, but imaging leaves a bit to be desired depending on the game.

Headphones for gaming is a strange world. I work in audio and have a few friends who work in the video game industry doing sound design/implementation, so I have a bit of a window into that world. Most games seem to be "mixed" (programmed really, but similar enough process) using either stereo speakers and/or whatever headphones the people working on the sound engine use. This is fairly commonly gaming headsets like astros, less commonly hifi headphones (which makes sense as the majority of gamers will be using gaming headphones, so you want the mix to sound best on what most people will be using). I don't know for sure this is the case at all major studios, but at least 2 of the big ones I can say for sure this is the case.

Because all headphones image differently you can't really make a game work perfectly on all of them. I generally got pretty fantastic imaging back when I gamed with Astros, but hated the sound, now I love the sound i get from my sundaras, but the imaging can be a bit off, particularly with sounds that are supposed to come from behind me (using in engine 3d/surround/atmos emulators). I prefer better sound quality to imaging, though if I was trying to be more competitive in pvp situations I might look for a different pair of headphones or iems that image better with specific games.

So basically no one headphone or driver type will be best for all games, and it's ultimately down to what you like best and what compromises you prefer. Ideally we'd all play on surround or Atmos speakers for the best experience, but very few actually do.