Can't see how the gun would operate without a battery or super cap.

Both have the potential to discharge when left unused for a while.
Keeping it on a charger 24x7 limits to ability to keep it in a secure container, like many safes, and opens up the chanced of theft.
Finding the "wristband" when you need it seems like a recipe to store the wristband with the firearms; similar to how people write their computer passwords on a post-it and stick it on their computer monitors, in an unsecured fashion.

I would really hate to have a need to use this, only to have it "Blue Screen" like my PC or phone or to have the battery be dead.

I would see the technology more practical if it could be used to quickly open a locked container, where my firearm is stored, such as a safe; the safe, also having a non-electronic method of access as well.