Eventually a system like this will succeed at getting some kind of scale. When that does happen, the smart devs will write tools that search for common issues

Eventually a system like this will succeed at getting some kind of scale. When that does happen, the smart devs will write tools that search for common issues in open source repositories, that also have bounties. You apply 1 code fix to 100 repositories, and that $80 bounty (x100) becomes an $8000 bounty. The result of that is that the easy stuff with a known fix will always be prioritized, and the hard stuff that require real engineering time will never be fixed.