In cities/areas with lots of high-rises and/or narrow roads, GPS doesn't work quite well sometimes. High-rises make it difficult to get a fix; and with narrow roads, a 20-meter error could probably gets you to the wrong road which is next to the one you actually want to get to. And at the same time, locations obtained from cellphone towers usually are not accurate enough.
While Class 2 Bluetooth can have an effective range around 10 meters, if we could have these Bluetooth transmitters installed on roadside (of course we need lots of them) or even inside shopping arcades, we will be able to use our phones to locate ourselves precisely on the street. The devices will even be able to pin-point us to the exact shop that we want to get to. Also, having a shopping arcade indoor map that can be used for navigation is no longer a problem.