I have a full set of wood DPNs but hardly ever use them, usually preferring circular needles...because two tips and a cable are easier to keep track of than five pins, they're much harder to lose one of, because I probably won't sit on one and break them, etc.
However, I'm glad to have them. For instance, I can make do for i-cord with things like a pair of tips if I have to, but much easier with DPNs.
I suppose I can understand a small LYS owner not wanting to bring in more stock, though -- it gets very expensive, trying to have all the sizes in all the materials in all the companies, etc.
I do have to say, though: they're tools, not a religion. Sometimes I wonder if people have forgotten!