Automated sources (options in FreeBSD, FLAVORS in OpenBSD).
Some ports are so buggy only packages would install. (How "they" do that, I don't know
, guess I should understand the Maskefiles I read
But, having better experience on Perl modules through CPAN then source install.
Have to check CPAN and source install over a while to see how updates are, or are not, taken care of between the two sources.
Nothing is black or white in the *nixes.