Bounty campaigns to me is not and will never be a waste of time. Reasons being I have always been profitable from it since I ever started doing bounties. The thing with bounty campaigns is always endeavor to join a legit project and be faithful to your bounty tasks.

Specifically bounty campaign are not wasting o time because you can earn money here if you can joined in one campaign but before you joined check all if this bounty campaign are worthy and you are not wasting time

bounty campaign can be a great source income for everyone and maybe it could be a passive income because we can hold the tokens for a long time and sell when the price is expensive. I don't think that bounty campaign is a waste of time unless the bounty campaign is trying to scam the participants because I think there is any bounty campaign that doesn't pay the participants and they run from their projects. with joining much of bounty campaign, we can earn many tokens which we can hold or sell and I think it's a lot of money for the participants.

Many people get high reward once the ICO of the bounty their joined are successful and they sell their coins with high amount so that's why it is good to them. But mostly of the bounty after waiting few months and the end of the bounty the coin they get has no value and sometimes the participants not pay by the founder of the project is scam. So if you get high reward to the biunty you joined you are lucky.

until now there is no way to trust ICO's is reliable and good. we can only predict it
I was a bounty hunter is a bit disappointed to see many ICO's who scam or participate for months to get shitcoin.
for now, I participate all the ICO I can .. so the more ICO's we follow the more chances are also to get the coins

Very true, there is no particular to determine if an ICO is legit or not. I've been a bounty hunter for numerous ICOs some turned out to be amazing even when I wasn't expecting much, while some were a very big waste of time and energy.  I believe @Ludmilla_rose1995 is right; the more ICO bounty we get involved in the higher the chances of getting coins/tokens with a good future.   

a reliable bounty campaign? well, I do not believe that there is a master or super user who can really understand about bounty campaign is good. maybe they can only distinguish the really real and not. the rest they are just guessing from intuition. like some time ago, a very senior person in the world of crypto said that project A would be successful and would be very profitable to follow the bounty campaign they held. they are successful and really good, as a token of their thanks to bounty participan, they give a little token for them, their tokens are valuable but they only provide garbage. they are so greedy that they forget the bounty hunter. so there is not a single bounty that is really good or bad, there is only bounty campaign with real projects and scam

well now this bounty gives us pasive income big enough. can even be a job if it is serious in working and get it in an easy way. everyone can do it if they intend

Depends on the coin.
If the coin you participated in the bounty has a huge success fast then you will get more money.
Some bounty campaigns pay a lot, good to sell at the beginning without waiting.