Bounty campaign is a good way for projects to spread the word and gain publicity in the cryptocurrency market. But it is not the best way to gain investors. Good projects don't depend on bounties alone to promote their token sale.
And this is because when bounty hunters post about a project, majority of these posts is only seen by other bounty hunters and not to the real investors. And these posts are just basic and can not convince good investors to invest.
Bringing in the investors and funds depends on the team's marketing ability and their ability to close deals. This is why good projects attend a lot of crypto events and network with people.
Though bounties help a project to create popularity and hype among crypto users, the main investment and funds is brought in by the team's marketing and closing ability.
Very true about all your statement, that success of a project is not just from the bounty. I agree with you, that most bounties, especially social media bounties are only seen by bounties and investors rarely see or are interested in bounties. Important points from the project marketing team by attending various events about crypto are important things from marketing to attract investors. Bounty especially social media is only to achieve the popularity of the project among crypto users.
In addition to this some of bounty hunters too are investor some might have interest in that particular coin beside promoting them they might buy some of the coins during Pre-ICOs, bounty hunters ensures their is a wide coverage in promotion of that particular coin the importance of hunters in marketing and creation of awareness can't be overemphasized take it or leave it.