my decisions are not open to discussion. Allowing an animal that can easily kill you "decide whether or not to listen" is way too risky.
I don't use it with the attitude that the horse can make his own decision whether or not to listen. I don't believe it cannot be used with force or pain either, although it's obviously a bit less able than a bit or a thin rope halter over a sensitive nose or such. I don't believe it's a good idea to attempt to control a horse with pain though and in normal situations, I wouldn't consider it any different, control-wise to a halter. BUT when probability of unthinking reactions is raised, such as when out & about in traffic or such, I don't think it's about deciding, but you need to have the ability to MAKE the horse listen.