Do we really need CAPTCHA for version 2? (one argument for it would be to have the possibility to be independent from Akismet)

I have a forum using version 1.7.

CAPTCHA works very well since it allows my forum users to be able to post without having to register. Not making REGISTRATION a requirement increases the number of posts and discussions in my forum, and having CAPTCHA deters spam. So the two together work very well for my forum.