This is one of the surviving improvements from JF Bastien's P1152 which was initially successful in deprecating most of the spurious use of volatile from C++ with a view to some day getting in there and actually doing MMIO properly.
Unfortunately too much of this will be unwound in C++ 23 because WG21 voted to un-deprecate all the volatile compound operators despite knowing nobody could even offer a rationale for why or how most of them would ever be correctly used.
P2327 would be in my "not angry just disappointed" category. Of course WG21 think rotten archaic C code should be valid C++ 23 and the belief from embedded devs who write this stuff that it's probably all fine despite no evidence whatsoever should be enough to sail through committee.
WG21 voted to amend the draft to un-deprecate all of the volatile compound assignments instead, at Kona IIRC.
Unfortunately too much of this will be unwound in C++ 23 because WG21 voted to un-deprecate all the volatile compound operators despite knowing nobody could even offer a rationale for why or how most of them would ever be correctly used.