CAPTCHAs are annoying, it's as simple as that. Although you might prevent the average script kiddy from automating filling out forms, it is not perfect. And then there is the issue of visually impaired people (they can't see the image).

I for one truely hate these systems, for a lot of them are just not readable at all. If I cannot fill out a form because I cannot read such a dumb picture, I skip the form altogether and go somewhere else. Besides, I love WWW::Mechanize ;)

So, before rushing into such means, see if you can't solve the itch another way. You are a Perlmonk, so there must be more than one way to do it ;) For instance, if you want to prevent comment-spam, look at systems such as b2evolution's antispam database, or linkcondom.com