Epic bought artstation, bandcamp, and, sketchfab. I don't know for sure, but I don't think any of those are very profitable. They're almost like resume hosting websites for game developers. 3d artists show off their work on sketchfab, artists show off on artstation, musicians show off their work on bandcamp.
My impression is that epic bought them for sort of the same reason Microsoft bought linkedin. They don't make tons of money, but they enhance the pipeline of artists and musicians available to the game industry.
Of course I have no idea if that's why they did it, but epic has definitely shown interest in steering the direction of the game industry in the past, and aligning the talent pool with their way of thinking is maybe a good way to do that.
In Bandcamp's messaging when they were acquired, expanding these payment systems was a major highlight. Combine this with Epic's messaging against Apple and Google about opening up billing on mobile platforms and major goals becomes very clear. One of these major goals can be a subscription service but to me it's obvious they're wanting to get into the artist -> individual creator/studio licensing environment for game/movie creators who already rely on Unreal.
The good news about this is that none of this should impact Bandcamp negatively, neither as a consumer or an artist, not unless you see more avenues to sell your music/merch as a bad thing. Bad news is your favorite Bandcamp artist will sell out ;)
To prove you can run a marketplace with lower commissions since the Epic Store was shown to be running at a loss, which hurt their case against Apple. Or so I’ve read.