Principly, I believe they would work very well. The fact that the hanger itself is shaped to hold the suit open rather than flat is enough to help dry the suit, so my vote on principle is that the unit will work good.
Practically, however, I am not sure that it would be worth it for occasional diving, especially travelling. If you lived in a beach diving area and dove twice a day every weekend or so and had a routine going in your garage, then I would get one for quick drying between dives, or to pack the suit quickly in a dive bag while you eat lunch. Otherwise, my suits dry fast enough hanging off a tree in the sun.
If you are driving to a dive site and want to dry your suit to pack it before you leave the site(and avoid the all too familiar stench), it might be a good idea, come to think of it.