>no mention of cost Means expensive chemistry. >targeting aircraft first Means expensive chemistry >no mention of durability If they were highly durable this would be an important feature so they're likely not. Sounds like these are going to be expensive special application batteries.
FWIW: lithium-ion was also expensive chemistry. If the promise matches the reality, supply chains will eventually realign to the point where consumer applications become feasible.
You've got to balance so many factors to commercially release a battery: safety, durability, reliability, weight, energy density, cost. You can build cheap batteries, they just have some terrible characteristics.