Why perlmonks isn't using them?

Because PerlMonks isn't guarding any significant secrets, besides the combination to the St Wall shrine's maintenance access panel.

Seriously, we allow posts by Anonymous Monk, which doesn't even require any kind of registration. The site has a moderation policy that seems to work fine for dealing with the occasional grafitti, and we use simple login techniques that also seem to work fine for our lightweight needs.

The account numbers for the saintly fortunes are all stored off-site. ;)