I'm a bountyhunter, or better: I was.
I'm a translator & did a sig or two.
In one year I made about 15 translations. Some were just ANN, some ANN + BOUNTY & some including WP. So what was my ROI?
I spent about 3-15 hours/project.
I researched for 1 hour/project
I spent about 3 hours/project communicating & reading Telegram/BTT
Just some facts:
3 out of 15 projects actually released a coin that is worth something.
I made about 50$/hour ranging from >1k$/hour in december 2017 to almost nothing these days (that's why I stopped)
3 projects were proven scams
7 more projects are still 'pending' with an inclination towards being scams/dead projects.
50% of the money comes from 1 project
40% of the money comes from another project
I had to wait 1 month for the most profitable bounty.
I'm waiting for more than 6 months for about 10 projects (of which I assume I will get noting from at least

SO: was it worthwile? yes BUT only thanks to the crazy bullrun. Would I recommend people for participating in bounties NOW? HELL no...
Such problems occur very often with me and several other participants. if we conclude this is our risk, bounty hunters. therefore, problems like i don't stop us from hunting for prizes....