It’s a subtle thing. It sounds like the money is safe. And it really is safe in the way that the FDIC handles: the depositor is protected in the event of a bank failure. It’s just that the depositor in this case is Yotta, not their customers, and there are potential problems beyond failures of the banks holding the money.
Note that this general scheme of “we’re not a bank but we’re as safe as a bank because we put your money in real banks” is not completely crazy and is sometimes used by serious financial institutions. For example, Fidelity offers a cash management account that works this way. So it’s not an immediate red flag on its own.