>Nobody knowns of the NIST curves have backdoors. Nobody know s if Dan Bernstein's curve has issues.
There are still some differences. NIST provides some curves and doesn't explain much about them. You can read up how DJB choose the curves. It's a very neat and tidy process that is easy to follow and very reasonable.
ECurve isn't terribly more complicated than RSA, they both rely on multiplication, though EC does it in 2D space and RSA in Modulo space. I have implemented EC myself, the underlying math isn't that much more complicated, really, than RSA.
>I don't understand the argument of dictating a key over the phone. If you care about that use case, you can just a well dictate the hash of an RSA public key.
Not only dictating over phone but for example typing a SSH key over a serial line while not being able to copy-paste directly. I've had to suffer than with my RSA4096 key once and it's NOT pleasant at all.
it also means you have much less overhead for the protocol (DH and KEX with Ed25519 only need 32 bytes of space per step instead of kilobytes)