There is considerable economic value in being able to control the eyeballs that visit the large subreddits, so it's expected that mods will want to monetise their power somehow.

r/HailCorporate sometimes goes overboard with their paranoia, but they also have clear evidence of how much reddit is gamed by users such as u/gallowboob

IIRC GallowBoob was known to work for a company that advertised things on Reddit, and was still allowed to become a moderator of a large number of subreddits. He then used that power to remove competing posts and ensure his own reached the front page. Absolute insanity.