Not a dumb question. The overlay is pretty much invisible in the dark even with the speedo light on. I'm back trying to remember what speed I'm going. The speedo I have even has MPH marks on the face itself and they're very hard to see at night.

I just like the idea of being able to glance down and check my speed. The bike speedometer seemed like the easiest and cheapest solution. I like the idea of the GPS too. I'd rather mount the bike speedo on there and forget about it and not have to worry about it being stolen (they're cheap).