I use it often for control, but sometimes to finish. If don't get my legs in the right spot on insertion, it can be hard to finish as a choke. If you don't care about the person, you can just smash the shit out of their face, but that's obviously not a nice thing to do in training and I only actually do that to a few people who would do the same to me.
Having taught it many times, the number one problem that I see when people try to do it as a choke is that they squeeze their legs together instead of straightening their legs to finish.
The control can put a fair amount of pressure on the face and neck, so sometimes it's not worth adjusting to get the finish, because it can be very uncomfortable for the person on bottom. If it's a situation that you are comfortable saying, "Fuck this peron's comfort", then continue to control/pressure the arm, and keep adjusting until you get your legs in a decent spot on the neck with minimal interference from the face or shoulders. As you would a rear naked, or any other choke, keep the control and work the position till you have a more ideal choke, then put on the pressure.