I had a discussion with my mechanic for the heavy duty tubes. His son is a motocross competition rider, so he has a very solid view on this matter and he also owns an ATAS as well...
He told me that the heavy duty tubes are a must for competition where the pressures re pretty low and the hits against obstacles that may tear apart a normal tube, are inevitable. BUT, if it would come to the case of stepping on a nail, the heavy duty tube will get a nice puncture as the normal one would.
He definitely do not suggest it for normal use for the following reasons:
1. they do NOT prevent punctures of the type we would encounter in normal riding.
2. they are a PITA for installation/fix
3. They are super heavy, affecting the gyroscopic phenomenon
4. They tend to run hotter.