The fatigue aspect matters too, but another important point I was trying to get across is that not all reviews are created equally. In a working, well tested, properly factored system, with a high quality PR, I can do a cursory, local analysis of the new code and be very confident that it works. AI code I've seen is ... not that. I wouldn't be comfortable in that review without manually checking preconditions and postconditions, defining invariants, examining lifetimes, and a host of other activities. Moreover, for a greenfield replacement of lots of SLOC, I'd expect that most of the code for the early PRs can't even meaningfully run or do anything important, making any sort of broader architectural analysis impossible.

I could see a world potentially where they came up with a magic prompt allowing each proposed PR to be cohesive, shippable, well factored, and everything else you need to be able to actually review it at a higher level and be comfortable with the results, but I'm skeptical. That's a major innovation if they managed to do so even as a one-off, and that wasn't the thing they highlighted when talking about the project.