I understand that people have varying agreement on the negative aspects of signatures, but can someone tell me any positives?
Kinda makes pages more colorful
You can always just disable them. If majority disables the signatures, it is as good as that. The community makes the choice.
I personally agree with shorena.
If someone makes an account for every one of his posts, I wouldn't care as long as they aren't pointless meaningless posts.
But wait, there's more...
Allow people with not enough money to buy a forum banner still promote their business in their personal sig space.
Offer a decent visibility for the money, a banner on one of the big Bitcoin sites would cost much more than a small forum campaign.
Campaigns popularize Bitcoin. I'm sure some of the posters came to Bitcointalk because they heard campaigns pay much better than faucets. IMO, bitcointalk campaigns are currently the easiest way to earn coins. Don't require you to own a bank account and register on an exchange (especially that some exchanges request an ID).
I don't see any negative sides. Spam is not a negative side of having the signatures! If forum did not allow to use sigs, people would spam links or PMs, or use their avatars to advertise and still get paid for it.