Merit was made to determine one's post quality.
If someone buys and sells merit it means that he abuses the system.
I can guess that Merit trading is forbidden and those who try to trade Merit will probably get their thread to be deleted.
Merit also very helpful as it gives users the option to thank other users for their posts.
An ability that wasn't available before.
I'm really trying to give it to my brother and what happened moderator has deleted some of my posts, before I did not understand what happened, when my intentions to help my sister to rank, I pity the activity she has 100 more but in can not go up rank, until now still remain "jr member" because she do not have merit.
This is really a good thing which has been introduced as it gives you an opportunity of getting an extra reward of your hard work and the efforts which you put in while working there in signature campaign.
This merit is something which cannot be bought and that it is not an appreciable thing as well to go for buying of such kind of thing because this is something which you are doing wrong with yourself. You really need to earn it.