That exception is experimental and somewhat limited; Only allows "well tested, high-quality" PRs on parts of the codebase that have a low probability of causing soundness issues, and it has a seperate review process with much higher standards.

And it requires the reviewer to agree to the use of LLMs ahead of time, before the PR is opened.

IMO, it has a high likelihood of degrading to a closed system, where some programmers with a good track record have little issue merging LLM generated PRs, while anyone without a reputation will struggle to even open an ai-assisted PR.