I don’t see why artists would receive money for music you purchased on bandcamp, unless I’m misunderstanding what you’re saying. It isn’t a streaming service. The only money exchanged is the money to purchase the album. It’s not monetized otherwise.
You might be able to stream some stuff you haven’t purchased, but artists have full control over what you can listen to and what you can’t, so those are treated more as a preview of the album rather than a “stream” in the Spotify sense.