Productivity gains are substantial but vary by task complexity: GenAI accelerates OSS development in more ways than simply writing code faster. Respondents estimate average time reductions across all six OSS development activities measured, including proposal discussions (19%) and code authoring (52%). For high-complexity tasks, however, 21% of respondents report taking more time when using GenAI.
You lose some you also win some though.
Everything still goes through human review though regardless.
It just shifts the time spent from writing code and other things to rewiting code and reviews most likely
If they've never received a patch potentially from someone too, it's going to be more likely to be bad code too that can be reviewed fairly quickly