The question mostly becomes, how much do you trust the creator of Inspector Gadget and a bit child actor with the guaranteeability of every Tether? The first full-scale run on it that shows an exchange can't be fulfilled in a timely fashion brings the whole enterprise to its knees, right?
The problem has now become that enough people think these instruments are legitimate that, like most questionable financial vehicles, when they collapse, some government entity will be required to bail the bad guys out and shift the cost onto anyone who was unlucky enough to be within the blast radius of the whole thing. Which is pretty much all of us at this point, either directly or indirectly.