If they have one of those fit bike thingies then yeah, offering it is a good service otherwise it's just marketing.

What might be cool is a DIY fit machine/booth where you put the little reflective thingies on your joints, sit on the machine and pedal, the computer films you and measures power/angles/technique, makes automatic adjustments to fit, you hit some buttons on a touch screen to put in preferences and voila. When you're done a purchase list prints out based on what the LBS has in stock or can get. Would cost a fortune but would be cool as hell. Jeez, now I want one.