I suspect less that 1% (or 0.1%) of Arduino applications need speed that is faster than digitalRead or digitalWrite.
if those functions are too slow then I think a user will benefit more by learning direct port manipulation than by using, without understanding, some rather esoteric macros. In my opinion the knowledge gained in learning direct port manipulation would be much more widely applicable and will provide a useful grounding in the internals of the Atmega processors and microprocessors in general.
Also, if a user discovers (as someone almost certainly will) that one of the macros does something unexpected what is s/he to do? Spend time trying to understand and fix/modify the macro? Or spend time trying to fix his/her own project?
...R