There are many occasions (for me) when this is the preferred outcome - many of the AUR things take significant time/resources even to update… whereas an ‘average’ (if there is such a thing) main repo update can be done in under a minute (if no kernel).
That’s my excuse, and I’m sticking to it! Mainly I just like to do separate things separately, I suspect - not to mention that I like to select which AUR items get updated, and which skipped - I am not sure I have that choice with saving max typing with just a yay.