Curt,
They should last a year or so. I worked on Bluetooth 4.0 or Low Energy. Their goal was to create a sensor that used so little power that the battery life in operation would be indistinguishable from the batteries shelf life.
Beacons we’re a big deal for a while. The idea is that when you are in a target store, you run a target app. The app is constantly looking for beacons which are coated in strategic spots. By looking at relative signal strengths of various beacons, the app knows where you are in the store.
There are some benefits:
if you want to find something, the app will locate it and guide you to it.
You can input your shopping list and the app will plan a route for you.
If you and your spouse both run the app, it can guide you to each other.
Theres also creepy stuff:
The app can serve up targeted adds based on your location.
The app can observe how fast you move and when you pause
I don’t know of any implementations of beacons in stores. As I recall, Macys played around with them. Early on, someone realized that you could tag your luggage or your kid and that’s where most beacons are used.
As I recall, a beacon is a Bluetooth chip that happily transmits a unique number when asked. All the brains are elsewhere.