The thing about head scissors is that you more or less have to use them for control, as getting a real choke out of them is difficult against a good grappler, leaving only a crank as a finish, which isn't legal. As a device for control, scissors aren't a bad move at all. As long as you're putting a lot of pressure on the head/neck/face, have good enough balance to ride the move properly, and can make a safe transition from there.
It's one of those moves that you don't see often, but it's still a fine move. Remember that Marcelo Garcia really opened the eyes of the Jiu-Jitsu population to the possibilities that can come from a simple arm drag.