The fact that there is a lot of scam has to do with lack of regulations and penalties for questionable and illegitimate ICOs that have promising projects, but mostly fail to deliver on their promises as they are SCAMs. As for the bounty, it is extremely difficult to identify the reliable ones. But it is possible provided you did thorough research on each project you are going to participate in. First of all, the team. Who they are, what they have already achieved in the past, what companies and industries they come from. Secondly, the idea of the project, how relevant it is. There could be a nice white paper and roadmap, but the product could be some crap. And last, the feedback from the subject matter experts should be reviewed and evaluated, because mostly if the project has got a good potential, the experts provide well grounded feedback. The bottom line is you can find one project with great potential instead of 10 scams. But this project could shoot out and make you some nice profit. Therefore, having said all above, it is worth to participate in bounties!