[throwawaymaths]

You don't have to query all checks at all times. You only have to borrow check when you pr to main. What is the sum latency of the coder dealing with conceptual problem of satisfying the borrow checker at every stage during an arduous refactor where they don't fully have the destination model in mind (and might want to try things out only to discard them). Versus, just ignoring it, seeing how the chips fall, and fixing ownership errors in one or two passes at the end once you've settled om the code structure? Of course you don't have to take the full round trip-to-someone-else's-computer latency either. If you can run it in CI, I presume you could run it locally too, and borrow checking is not particularly slow for the computer.

You're also not (because one can't) quantifying the problem of a developer getting exasperated and saying, fuck it, it passes the borrow checker, good enough, instead of actually taking the time to make their code legible first and then making sure it is memory safe. This absolutely happens.