LOL that art thread definitely got too out of hand. A lot of users saw the high potential of them actually earning merit without having to make decent posts hence it's really not surprising that they're taking full advantage of it while the thread is still up and active until it gets old enough to be locked.
First, the art contest will end in next three days, then they will stop soon.
The contest ends
Nov 22 18:04:28 UTC; submissions after that are not guaranteed consideration. BTC will be sent all at once, probably a few hours after the end time.
Second, it is as same as the merit sytem, participants of the art contest have to submit good arts in order to receive merits as users have to make good posts to earn merits.
Without a prize and Merit, it probably would have been.
Maybe it is not true because some jokes like April Fools also attracted them.