Given that the only comments worth having are typically those that explain why, and an AI would have a hell of a time knowing why code was the way it was, there

Given that the only comments worth having are typically those that explain why, and an AI would have a hell of a time knowing why code was the way it was, there's very little chance that this does anything but add noise. It's exactly the type of "productivity enhancement" we should expect from AI right now. That is, as long as you measure productivity by lines of code and nothing else that actually matters to the business.