Utilisation of stranded (worthless, unable to be used) energy, makes use of renewables during oversupply to balance electric grids, increasing renewable energy viability, and use far less toxic chemicals in their production.

And not even to get started on the inefficiency of carrying around a giant battery all the time. Clean air? Only around it, not where its power comes from, nor the lithium settling ponds... I'm really looking forward to the whole parking garage that burns like fireworks from so much overheating lithum batteries all in one place.