The MKCRYPTO=no option was introduced long ago, when there were legal
issues regarding the export of cryptographic code from the US.
Since that time, [...].
It was suggested on icb/irc today that we should probably just remove
the option completely. The export restrictions no longer apply, and
there doesn't seem to be anyone able-and-willing to maintain the
option.
The USA is not the whole world. There are still places where the use
of crypto is restricted or forbidden. I don't know whether anyone is
building crypto-free distros for people in such places (I'm not, but
that doesn't mean much), but it strikes me as one possible modern use
for the option.
Of course, the second reason cited still applies. If anyone actually
still has (this or any other) use for MKCRYPTO=no, now would be an
excellent time to speak up - and, preferably, step up.