I don't see anything particularly wrong with that. They're not selling or buying merits. What they're offering is not too different from e.g. sig campaigns that require to have a certain number of earned merits or pay more to users who have a certain number of earned merits.
Exactly what i was thinking, except that in this case it more like the more merits one has, the more tokens one gets.
The only bad outcome if not well handled is that certain members could attempt to abuse merit system (buy/sell merits) before participating so as to get more tokens