Personally, instead of DNSCrypt, I prefer CurveDNS

Neither is a replacement for the other; they're orthogonal. They solve different problems.

You should use both of them.

From the CurveDNS link you posted:

CurveDNS supports:

Forwarding of regular (non-protected) DNS packets

These are being sent in the clear, and your ISP is most certainly logging them. You should tell your CurveDNS resolver to use a (local) dnscrypt-proxy instance for resolving "regular (non-protected)" queries that don't have DNSCurve entries. Then you have the best of both worlds!

The question I have for DNSCrypt fans is _why_ AFAICT no authoritative DNS servers are using it

Because DNSCrypt is only for querying recursive resolvers!

... and DNSCurve is only for querying authoritative resolvers.

DNSCrypt is link-level encryption between you and your recursive resolver (the thing you put in /etc/resolv.conf).

DNSCurve is link-level encryption between your recursive resolver (or you) and the authoritative resolver (like this one, which is authoritative for cr.yp.to):

    $ dig -t NS yp.to
    yp.to.                  3600    IN      NS      uz5jmyqz3gz2bhnuzg0rr0cml9u8pntyhn2jhtqn04yt3sm5h235c1.yp.to.

It is a shame that the two names (DNSCurve and DNSCrypt) are so similar.