I believe that bounty isn't not that much worthy anymore to join unless you hit a jackpot by having a successful project. The type of campaigns you mentioned is I believe past their time already. Those niche becomes hot for a certain time until project that applies those on their projects doesn't help anymore in accumulating funds in their project which leads to the main project failed. I don't really have any idea on what is currently happening on bounty campaign scene right now but the last time I heard is there is an increase on number of non-paying campaign, Small awards and scammers which is certainly due to bad market situation.