Obviously it is used by the excellent Dist::Zilla::Plugin::AutoPrereqs,
but I've lately been doing some work on a 5-year old dist that is run on 50+ off-site machines.
It will take me a while to convert it to Dist::Zilla,
but in the meantime I have been able to keep myself from breaking things
with just a few lines of code in a Makefile that scans for all the prereqs and installs any missing ones from cpan.
A lifesaver for us absent-minded fellows.