The difference is that if it's contained and not deleted, there's a good chance it won't be re-created, giving a reporter and a mod some more work to do. Again and again.
I never liked this principle. Too much work for the mods, so let's just sweep it under the carpet or move it elsewhere and hope no one gets hurt. How well is the Serious discussion board going, I wonder? That's the reverse of investor-based games: try to redirect quality posts there...One aspect is that the underlying assumption expects the ponzi promoter to repeatedly post until publish their thread (and then cease), but why would anyone ever stop there? Follow-up advertisement posts/threads from alt accounts (most likely how the thread was initially created) will simply grant the investor-based thread more opportunity to spread, and the board hosts their platform. The incentive is much greater when you have a lasting thread - subsequent advertisements carry more impact.
I don't see any reason why someone wouldn't automate ponzi scams on the forum if they took a look at the scenario. Low volume board, so they can establish their personal ponzi threads; minimal/slow moderation forum-wide, so your advertisements will always be posted; no new user requirements, so you can set up the massive account farm you want.
