I've had a pretty good experience offering bounties on my own projects:
- https://github.com/orgs/com-lihaoyi/discussions/6
If you look at that thread, you'll see I've paid out quite a lot in bounties, somewhere around 50-60kUSD (the amount is not quite precise, because some bounties I completed myself without paying, and others I paid extra when the work turned out to be more than expected). In exchange, I did manage to get quite a lot of work done for that cost
You do get some trash, it does take significant work to review, and not everything is amenable to bounties. But for projects that already have interested users and potential collaborators, sometimes 500-1000USD in cash is enough motivation for someone to go from curious to engaged. And if I can pay someone 500-1000USD to save me a week of work (and associated context switching) it can definitely be worth the cost.
The bounties are certainly not a living wage for people, especially compared to my peers making 1mUSD/yr at some big tech FAANG. It's just a token of appreciation that somehow feels qualitatively different from the money that comes in your twice-monthly paycheck