The uncertainty around their origin (a foreign country who until a few years ago was hostile to the US) would preclude them being used by US government agencies (who depend on NIST for the stamp of approval).
[0] https://blog.cr.yp.to/20140323-ecdsa.html
Edit: my point here is that America would have to trust that there was no way that the Russians had added backdoors. Given their history and the current political climate I can't see that trust coming soon.