Naw, "all" really implies a lot. To my observation if there is a fixed, even "failesssafe guaranteeed we sssswear" interest rate then something sneaky keeps going on.
Mostly ponzi who have to exitscamm at some point in future. Regardless if it is investing into whatever it is to invest for, over there. Mining operation, special trade methods, regardless.

I'm keeping my BTC and currently beeing on the lookout for small programing tasks.