Bluetooth Low Energy desperately needs a killer application
Bluetooth desparately needs to be able to maintain a connection, not just for a few days, but also for the few days after that when it randomly disconnects, fails to reconnect without manual intervention, restarting everything, unplugging and plugging the dongle into a different USB port, etc.
Ok, so all of that probably isn't part of the Bluetooth spec. In that case, I'll revise it to "bluetooth desparately needs an *implementation* able to maintain a connection."