Believe it or not, They are not all that difficult
to master, It just takes practice. When I was in Law
enforcement, I carried one on my duty belt. The Sheriff
didn't really like the Idea of carrying a fixed blade knife.
But He didn't mind Butterflies. This was after I convinced
him of the merrits of a knife that could be opened with one hand.
That knife is now serving in the CIA with a friend of mine.
I gave it to him when I left the dept.