I can see how for a mac user that relies only on MuseScore and Apple-made apps, the lack of an auto-backup facility in Dorico could be irritating.
On the other hand, those of us that have jumped ship from Sibelius have never been able to trust its backup (dys)function, and those of us who use Microsoft Office on a mac have only had auto-backup since January this year (and it only works if you’re on Office 365 subscriber).
From where I’m sitting, Cmd-S really ought to be hardwired into the brain of the user - let’s face it, most of us have been using computers since long before auto-backup was really a thing, in any software.