Doing a stablecoin to replace something like the USD is an extremely difficult problem. Reserve.org is one company which understands the gravity of the issue and is committed to producing a stablecoin for anyone, worthy enough to replace the USD.
It's also a solved one.
There is one party on the planet that can credibly solve this problem, and it's the Fed. Walter Bagehot wrote about this effectively in 1873 [1], it's still comprehensible, and it is to the Federal Reserve Act what the Declaration is to the Constitution.
Every U.S. dollar stablecoin issued by someone who is not (a) the Fed and (b) fully reserved is trying to solve the impossible trinity [2].
[1] https://en.wikipedia.org/wiki/Lombard_Street:_A_Description_...