This new users I'm thinking would be alt accounts of users on the forum, probably accounts were created just to try and earn some of the BTC price giveaway.

The good thing about the art contest is that as long as a user does a good artwork, then they're going to be rewarded, either in BTC or merits, not minding if they are shitposters, going through their post history, red tagged or any of those. It's wonderful and it brings the community together, and that's what birthdays celebrations do.