With the cost of $15 per merit, it means that a Member need to spend $1350 for more 90 merits to become a Full Member.
The cost, in my opinion, is to expensive. Additionally, how long the buyers (of Full Member, for example) can get their money back?
Years, maybe, and there are some other risks such as being discovered as merit abusers, and got red trust then don't have chance to join good campaign.
Moreover, even they buy 90 merits to be promoted to Full Members, if their post histories contain mostly shitshows, they won't have chance to get acceptance, too. Because managers do not only care about merits, they also care more about post quality.