Problems arise when these accounts are used to abuse signature campaigns or for merit abuse. Airdropped merits on these accounts have become something that can be sold for a decent price. For example, Legendary accounts get 200 merits (in my case), and if you sell them for only $5 each it is easy $1000.
I saw many in the marketplace, many merit abuser selling merits. They sell each merit at a much higher price. Cost per merit is $20!

You can check here :
https://www.fiverr.com/dollydeval/supply-bitcointalk-merits-for-your-bitcointalk-account?ref_ctx_id=72b2b24c-2675-4e12-8695-d6011172768c
Many merit abuser may not have been caught by the community. But what I see is that, the users can not go too far by buying merit, they get stuck at a limited rank.