I'm not sure that I have a moral right to tell my story because it so happened that I did not put any personal dollar, only time. I raised a little capital by completing bounty tasks of various types. But I can say with confidence that my whole story is 80% scam. Despite the huge amount of time spent on companies, I never received payment for my work. To be more specific, I can summarize the statistics of participation in bounty companies in 2018-2019, so that the next one going this way would know what awaits him on the way.
And so, on average, I spent 2 hours a day, 6 days a week on tasks. It turns out about 52 hours per month. Of these 52 hours - actually paid, it turned out 10 hours (here you have to believe me, although I can give my calculations in excel  ). Considering this, an hour of my work was worth 70 dollars. Consequently, I received less than $ 2940 per month. For your information, bounty companies last a couple of months on average.
Summary: it is up to everyone to decide whether to participate in bounty campaigns or not.
From myself, I can say that it is rather unpleasant to waste your time)