I discussed with people working on aircraft components, and my understanding is that weight is a constant obsession for them. Propose a new system to Airbus/Boeing, and the first question they'll ask is "how much does it weight?"

Every kg saved is a kg more of freight that can be transported (or a little less fuel used to keep the plane in the air); save 500g for each seat of a 200-seat plane, and you can put one more paying passenger in the cabin.

Agreed. But for related reasons, aircraft aren't really designed for either the structural robustness or balance to deal with big heavy batteries, which is what motivated the clean sheet design.