You can't run a ponzi scheme without records the accounting skills needed to run one successfully are probably greater than the ones needed to manage an actual investment fund.
Actually, you don't need anything more than basic bookkeeping skills. What surprises me is that it is an online ponzi scheme and yet they maintain records on paper. This does not add up.
Again you don't run a ponzi scheme on that scale using "basic bookkeeping skills", you need to be a heck of an accountant to make sure that you have enough cash flow to pay out returns and make enough legitimate investments and constantly keep the money moving to make it appear that it's still there.
If you just base you ponzi scheme on I take 50% of every new payment and give out the previous 50% to my previous investments it won't really drag on for longer than couple of months, not to mention that you actually need to generate allot of financial traffic to both draw people in initially and keep the authorities of your back.
The reason ponzi schemes tend to snowball like this is because they run exceptionally well many of them have actually made some decent return on their investments (not anywhere near the actual percentage needed to balance out the "management costs" ofc) a good ponzi scheme is almost indistinguishable from a legitimate investment fund, they'll make tons of trades, constantly move money around and keep large cash flows on hand to make it look like all the money is still there, make regular payouts, and "silence" any panicked investor who wants to cash out early.
I don't know defrauding 1000's of people for years while keeping everyone in the dark including most if not all of your employees and making yourself look like a functioning legitimate business as far as casual financial inspections go sounds pretty hard to me, at least as hard as running an actual investment fund.
Regulators probe the market constantly if your trades don't add up at all you'll get caught in a minute lasting years and managing to steal 100's of millions or even billions of dollars doesn't seem something anyone could just pull off, I think you underestimate the intelligence and skills required to run these sort of scams.
Paper records aren't subject to remote access exploits by police or hackers. If you're running an illegal scheme in a surveillance state, it starts to seem like a reasonable decision.