That's of course true. Like we spoke before, any bastard sword is not a sledgehammer.
When the blunt side is used to strike, the targets tend to be (preferably unarmored) hands, wrists, fingers and head.
Yet we must remember that everything in real combat is about desperation. A smack with the blunt side of your blade to the mask or helmet of your opponent might give just the needed split second to change the angle of your blade and go in from a better spot.
There is the formal use of every weapon, and there's this unspoken array of stuff that you only understand through live practice or actual fighting. Often this stuff includes moves that your average historian would laugh at. And yet they work - when used by the right guy in the right situation against the right opponent. (At least if the stars are right. )