Would there be a benefit of having bluetooth 4.0 if some devices use older versions?

I have the iPhone 5 which supports BLE 4.0 and also own a pebble watch which also supports 4.0. My car however only supports bluetooth 1.2. Does this mean I will not experience the battery benefits of BLE since I will still need to connect to my car which is on the older 1.2 version of bluetooth?

Won't beinfit really