Board Thread:ROBLOX help and discussion/@comment-27689042-20170127190440/@comment-35592249-20180715210410

Probably because OBC is the highest membership you can get. There are plenty of people who want to get the best they possibly can, and in Roblox's case it is OBC.

And yeah, of course - the bonuses you get from it. I guess that sorta links to the point I just made, though.

(Edit: Yeah, DevEx is probably one of the biggest reasons for developers to buy OBC.)