Reddit Premium grants Redditors an ad-free experience, access to a "Members-Only Lounge" and a monthly allocation of "Reddit Coins." The coins are used to "award extraordinary contributions to Reddit." [1] Aside from showing a little badge, the coins don't amount to anything.

January 23, 2019 — In the midst of the Stoned and Single experiment, I noticed that a prompted post on Reddit, created by the official /u/redditpremium account, had been awarded a 'Silver' coin. An advertisement being awarded for it's "extraordinary contribution" seemed highly suspect. It got me wondering if the Administrators had quietly changed the Reddit Algorithm to boost posts that have been awarded—beyond the normal Karma of upvotes—and that the internal marketing team was exploiting its own loophole. So... I awarded my own ad coins from an old account to test.

References

Reddit Premium, reddit.com/premium