For skill-based games like Tetris Attack, external eurobeat increases my skill. But of course, the music and sound don't matter in TA, unlike Quake singleplayer, which is skill-based, but where the ambiance is half the point of playing.
For low-skill, engrossing games like roguelikes, JRPG grinds, or sims, podcasts make for maximum comfy. Armada for the Dreamcast sticks out as perfect for that, since a lot of the gameplay consists of a space road trip simulator. An armada of desert buses, more like.
As for VG as a musical genre… I mean, it's one thing to not like the Terran themes from Starcraft, but a lot of the appeal of VG music is the memory you carry from playing the game. It has meaning intrinsic to yourself, which you necessarily miss out on if you never listen to it while playing.
I also like the impressionistic character of a lot of videogame music, at least prior to the voice acting era. There's more to music as an artform than jungle monkey beats, and musical impressionism is a good example of why that is.