IMO, it's still worth it to join as long you can choose the best bounty but in the current status of bounties, I guess you will have a struggle on choosing one because even the decent projects still end up on being bad projects. Then, based on what I see on some thread here, it seems the year which bounty is good is in the year 2017. Although we see different failed projects in the previous months, I can say that participating in bounties is still worth it as long as you earn profit from it and your effort and time are not wasted. But, in this time some member here is now choosing the campaign who pay in bitcoin than the campaign who pay you in bounty token.
And to the OP, having bounty reports in your account will not spoil your post history and as long you didn't break any rules your account is clean and safe. If you really intend to rank up and want to earn something, I guess you should focus on contributing good topics, posts or guides that can help other members.