When I first started, it was because Perlmonks was civilized to newbies. comp.lang.perl.misc, at that time was a brawling, insulting competition between posters. There was this beast called Godzilla that would insult any newbie, claiming the question was incompetant; and there were regulars who would try to out do each other in making the better answer, mostly as means to insult the other guy's intelligence.

The most common answer was RTFM.

Perlmonks ,on the other hand, was considerate, the worst chastisement here is "show your code", or "I can't understand your question".

Now after a few years, as the perlmonks code base has built up, it's very easy to refer to past nodes containing code, and it has a nice web front end. It just is generally easier to use than the nntp newsgroups.