If you can kick high with decent power you can kick low with even greater power ... nothing wrong with practice in a full range of motion.
Tell Bill Wallace kicking to the head isn't effective. Ground to head at 75 MPH.
On the street I wouldnt kick someone in the head unless they were on the ground ... however in competition its pretty darn fun if you can pull it off.
check around 5 seconds in ... yup that's me sometime in the 90's.
Just an extra tool in the tool box in my opinion.
BTW cool video Jamie ... like the Wong Fei Hung music.