There’s plenty of good reasons to transfer update ownership to the Play Store, too.

I’m interested, can you give a few examples?

Besides, it’s optional. Options are a good thing to have.

That’s true, until it’s not an option because a “bug” converts your apps to play store builds, and until this option gains a non-optional feature that nags you every x days to googlify your apps and expects that at some point you will either accept or misclick it. This is not something unheard of, play protect already does this.