I see potential, but ultimately it comes down to cost, energy density and time to market.
4,2MWh in a 40 footer is more than the 2MWh we see today, but it is still not enough. A city in the 100k-region can be at the 80MW mark, so with 4,2MWh@0.01C it would take 2000 containers to be able to run that city for the 100 hours spoken about in the article.
Don't get me wrong, it is an incredible achievement, not least geopolitically, but for it to take off costs need to be low. If they are at price parity with LFP/sodium batteries I'll want 1 for testing. If they are at half the cost I will start looking for places to stack containers.