Yes ofcourse its useful for ICO as bounty programme is a paid form of large scale promotion globally on social platforms like facebook,twitter.Bounty participants are paid tokens or coins of the project for doing work like promoting the project in a very enthusiastic manner that people get convinced and invest in that project. Many ICO reach their hard cap within days due to it.They distribute a minor share to bounty hunters and raise millions by themselves so its really positive and useful.