The biggest problem a GENIUS or other fully reserved stablecoin faces is emissions.
$1 has to be surrendered for every 1 stablecoin created. This is tough.
The two demonstrable profit centers in stablecoins - Tether and historical MakerDAO (not the current Sky, ewww) - did so without full reserves.
The good news is that clever people CAN make a fully reserved stablecoin emit in other ways (although no one seems to have noticed yet, or they simply don’t want to for fear of the Law of Reflux).
The bad news is that emissions is just one part of a successful stablecoin. Circulation and redemption are the others.
Circulation being the most difficult.