of course bounty is very helpful in the success of an ICO because bounty helps attract investors to invest in an ico, if ICO but don't have a bounty then I am very sure if the ICO is not going to succeed
Bounty campaigns help the ICO project in such a way that they help promote the project as a means of advertising through social media and in this forum. The bounty hunters are helping the project by advertising through these campaigns, and this would help the ICO project to be known to many people as well as the investors' interests in the certain project.