Indeed, the small additional bookkeeping is the price to pay. I'm quite used to it, so I don't even see it anymore.

Is that all? These 5 less minutes of bookkeeping are the killer feature of monorepos?

Because, as far as I see it, there's an insane amount of engineering to make a monorepo work even at small scale. Are these 5 minutes per multi-project PR worth it?

I wouldn't be surprised these 5 minutes are largely offsets solely by the additional hours of CI testing time introduced by having to run tests on the whole monorepo at each commit instead of just the project that changed.