Not necessarily. I don't think the campaigns rely on profit directly from people, who wear the signatures. It's just that Bitcointalk itself is full of people, who are into the things, that are advertised here: altcoins, gambling, other crypto-related projects. Thus, this forum seems to be a very good platform with a target-like effect. For instance, advertising the above-mentioned things on popular platforms or on social media, like on Instagram or Facebook, even with targetting, wouldn't be that effective, IMO.

Anyways, I donated much of my earnings here in research, because I'm a scientist, and research funding in our country is very poor, so if you want to make a difference, discover things and publish them - you need to rely on your own investments.