How are they a ponzi when they buy low and sell high not just on BTC but across 200+ cryptocurrencies to ensure they get a profit but also ensure they fulfill the orders placed. I have not heard of ONE occurance yet where they have not delivered. Ponzi, I think you are mistaken.
Um.... You know what a Ponzi is, right? It "works" great, right up to the point where new money coming in can't keep up with payments going out.
Maddof ran for decades without "one" occurance where he had not delivered.