I think they are trying to avoid the probably very common scenario where you forget your headphones for a trip, nothing to worry about, just buy a pair from the Express machine, return them as soon as you are back home.
Perhaps Pivotal wins by being able to get a ton of enterprise engineers from EMC, turn them into Rubyists and scale their already very successful model. If they are profitable at ~100 employees, they would be even more profitable at ~150, ~200.