I was personally very hyped when I've seen this getting added on the server,but after trying it out for a while I've lost interest in it,as most criminals have.
Well,the payment isn't that good.You only make $300-$700 per graffiti/tag sprayed,that's even less than what you make on average from a house robbery,and don't forget house robberies also sometimes give you drugs!
I suggest increasing the amount of money you can get from spraying a graffiti,as the current payment isn't good at all.This or make it give you a solid money bonus($3k-$10k?) or a drugs bonus after spraying 10 tags.
I hope to see this criminal activity getting improved in the near future,as spraying graffitis was one of many peoples' favorite activity in the singleplayer version of the game,but here,it isn't really worth the effort.