Yes I think launching bounty and signature campaigns mostly are successful because it draws more attention to investors to invest in their project. But of course it also needs a good campaign manager to work with and is more experienced to help the team attract investors too.
True, it all depends on the manager who is able to manage the bounty and signature campaign well, as a whole many projects can succeed by doing a signature campaign that can be managed by a professional manager who can invite many investors who can get into itThis is an accurate description and one that projects need to understand as well. A few now choose to run their own, which is fair and of course good to hear. But they do not realise the amount of spam and useless bounty hunters that encroach on the site. They are only there to earn stakes, as much as possible, for dumping at the earliest moment.
Good campaigns have a similarity in good managers who not only keeps participants happy but give good value to the project by ensuring quality members and weeding out the spammers.
Bad managers give a bad reputation to the project. This can be even detrimental to the ICO.
Most campaigns have set rules with them anyway so the chances of spam abuse and cheating is limited. Success of the campaign also depends on the community support and development of the product. Sure a great marketing hype can spread word quickly but without a viable product, marketing is still useless.
