I think it is because
You might Poke Your Eye Out!
Seriously, the interstate commerce law is the stopper.
It's legal in many states to own one, but against federal law to ship them across state lines except for police, military, and maybe one-armed folks with a Dr's slip!
I really don't know what the big attraction is anyway, other then the "WoW", and "You Can't Have One" factors.
I own, or have owned, several Benchmade & other Autos.
One broke a spring which put it out of action, because Benchmade would not risk shipping repair parts to me.
They are all more sensitive to sand & dirt then manual openers.
And has been said,
they are no faster, if as fast, then a well broken in manual like a hole-opener AFCK, or any of the AXIS-Lock Benchmades.
rcmodel