I guess that, if all that is needed is a backwards pressure, using a neck strap technally will do the job ok, with the large advantage that it IS rather less visible, which IS important to "normal" patients. And probably both cheaper and more rugged.
I guess the advantage of the Interlandi is the possibility to change the direction of the pull force.
I have one of everything, and my favourite has always been th Interlandi: it's amazingly comfortable.