My personal opinion is, although there is obviously some negative effects from sig.campaigns they are most certainly good for the forum overall.
They incentivize people to be active.
They help create active threads, sections, SEO rankings etc. etc.
If people need a signature campaign as an incentive to be active then no, that's not good at all. And most of the traffic it helps create is utterly worthless. Watch
Patrol for a few minutes - what's the point of all that crap?
It will take us a few months to see the effects of merit. If that doesn't work out I'd rather see the signatures (and avatars) banned altogether, at least outside of the Altcoin boards.