Agreed, but adoption of Bitcoin will reduce "Cash" on your premises and this will reduce cash transports. If you were a robber and you had to chose a target between a merchant that are cash only and another merchant that has a "Bitcoin accepted here" sticker in the window, which one will you target?
I'd go to the merchant with "Bitcoin accepted here" sticker. Robbery, well for pros, always have planning before they go robbing any banks or merchants. They familiarize themselves on the establishment, where to go, where are the money, etc. So if a robber will rob a merchant that accepts Bitcoin, he has to know where the device and what device to take. This may sound absurd but having Bitcoin instead of cash is very much profitable for the robber
