Regardless of what batteries you buy, to be able to see rated capacity and other stats during and at the end of the charge is a great feature. Batteries do fail over time. I'm not too bothered about the Bluetooth functionality, but I would assume firmware can be pushed to the device via Bluetooth as well, so yeah, I guess it has merit.
Besides, if you want to only partially charge a battery just to get something working, then the stats come in handy for that too (I know I usually rummage around for a while looking for charged batteries for cordless mice etc...).
On face value, it looks like a fairly well designed product.