No doubtful, bounty campaigns draws a ton of attention to your community and enlighten potential investors about your project. But at the long run, is this development sustainable? Is it reliable enough to grow your project?
In the short period, bounty campaigns are great for projects, but since you're talking about in the long run then i would say it depends, now what does it depend on: everything rests on the shoulders of the project owners/managers, what they do after alluring investors for the short term, do they keep developing their project, or do they just reach a standstill, mind you that no matter how good your campaign is, if your project turns out to be bad or a scam, no investor would stay, thus everything falls back on the project, if it is a good one, then the development will definitely be sustainable, if it is bad, then it won't.