I've been wondering about that. When I used MacOS 9, I used MacPerl. Now that I have MacOS X with a BSD-based command line (aka darwin)(kind of...), I use Perl compiled for darwin. Why would one continue to use MacPerl when the Unix-based one is finally accessible?
I'm asking in all seriousness. Since /usr/bin/perl is pre-installed - what is the benefit for an OS X user in using MacPerl instead?
MacPerl is for Mac OS. Not for Mac OS X. Really, the only reason you'd want to use it for Mac OS X is if you want to use the Mac:: modules that are (currently!) specific to MacPerl/Mac OS, that don't yet work on Mac OS X.
Once those modules largely work on Mac OS X, there will be no reason at all to use MacPerl on Mac OS X, I'd wager.
However, many people still use Mac OS, and haven't yet or never will switch to Mac OS X. MacPerl is primarily for them. :-)
MySQL does not run on Mac OS 9. There is a MacSQL Monitor program that allows you to connect to a MySQL database via TCP/IP, and it is possible someone could use those shared libraries to build a DBD::MySQL. However, I usually just use DBD::Proxy/DBI::ProxyServer, since I am going to be talking to a remote DB anyway.