Rigid tapping NO, Semi rigid tapping(SRT) YES if you can dynamically brake the spindle motr with the VFD. You have to be able to stop and reverse the spindle quickly
The advantage of SRT over the tapping head is the tapping head takes up a huge amount of Z travel and tool length offsetting on a knee type mill where you may only have 5-6" of travel.
If you have plenty of Z travel then the tapping head works well too.
(;-) TP