Regulators are are also in bit of a spot because it's an entirely new beast. For most of the current use case crypto acts like unregistered security but in in some minor way it's also a currency. So regulators are biding their time because coming down with a heavy hand will attract a bad rep as big hedge funds are also getting into crypto.
Also, IMO current legal codes aren't good enough to tackle crypto at the moment, see this[1] for example. It's an active area of legal research so will take time to crystallise.
So these apps are slipping through this regulatory crack. Do they deserve to go to jail? I'm not so sure. But they do know what they are doing.
[1] https://www.imf.org/en/Publications/WP/Issues/2020/11/20/Leg...
It's relatively easy to deal with money-like substances that are precisely confined (closed-loop as they are called sometimes) such as carnival tokens, or Starbuck reward points. Problem starts when they start leaking into day-to-day finances.
I'm actually quite surprised that some of these scams (stablecoins being one example[2]) have been allowed to go on as long as they have.
[1] i.e. buying you at least a temporary reprieve as all you're winning is the argument that that particular law doesn't apply to you, not that they won't pass a new law and come after you using it.
[2] It sure looks to me like they're pretending to be defacto banks issuing their own defacto dollars and not so subtly assuring 'investors' a rate of return. The combination of these factors have historically been all but guaranteed to get damn near every agency of the govt on your ass.