This can be a big move into energy storage, where supply can be temporarily installed, removed to another site, or trains transporting the storage to site of usage?

Cost product and install cost and diy ability?

If they give out a warranty then it is likely to retain 80% capacity during the 20 year warranty period. Even first LFP batteries had a very good longevity. They could easily last > 10 years if managed correctly. So this is not out of the ordinary for updated tech.

The real question isn't how much degradation you have during first 5 years but what is the degradation curve and what is it like in 20 years?

Thing is, batteries are often times over-provisioned, 100% is closer to 90%. So your first 5 years of degradation could simply be the provision so it seems like 0, the drops.

I didn't see a price for the system.