I like the idea of local/distributed energy storage. I like the idea of harvesting "free energy" like wind and solar.
BUT - there will be adjustment/teething problems. Witness the Energetic Fires of Priuses and Teslas after wrecks that short out the batteries, and the rescuers Electrocuted while cutting victims out.
So, some kid gets an idea to recharge his R/C battery from the battery pack in the Basement. Firefighters facing a 2000 Amp Arc at the Battery room of a Residence.
Think of the interlocks, safety devices, and Government interference with implementation of "Reasonable Sized" installations in Single Family Homes: I contend that within a very few years, the gummint will have a cadre of inspectors,, like those for Elevators. Twice a year intrusions by " Inspectors" who will have to have access to your system. Testing. Certification. Mandatory, no-notice, replacement of expensive Batteries/components, like the FAA drops on Airplane Owners.
Put in your own systems soon, and Hope and Pray that such are "grandfathered in" without onerous inspections etc. Hope that Self-installed systems are allowed to be serviced by Harry Homeowner. Hope that Self-Installed systems do not give rise to Insurance Red-Lining, and huge rate increases. Hope that Self-Engineered and/or installed systems must not have to be removed to sell a home. Another Thirty Pages and Three Inspections, Twelve Signatures, and Legal boilerplate to read and assume liability for when buying/selling.
You ever see a Lead-Acid Battery Explosion? Lithium Battery Explosion? I have. I shudder to think about something similar with a molten electrolyte battery, or some even more exotic battery blowing up. Remember, the more dense the energy storage, the more like a Bomb the battery explosion becomes.