Well, if the administration will tolerate this kind of exchange, shitposting will not prevent. The number one reason why merit system executed in this forum is in order to avoid spamming and shitposting. Auction and buying is not tolerable because you are just buying the Smerit from others even your post do not have quality.
If merit is available to buy, Members who have enough money will benefit more by this system. In short, newbies cannot do a lot because they don't have enough money to buy.