Third.. Stainless Steel... EVERYWHERE.
Forth .. Hydrogen Embrittlement
Seriously..
Between the Wars and Geopolitics for the past hundred years....
The amount of $$$$$$ spent on deep sea oil rigs/drilling/etc....
Hydrogen, the most studied element of all elements...
If it was even remotely possible to use Hydrogen effectively, we'd be doing it already...
Well, FUD all you want.
I've actually worked on Hydrogen powered vehicles and there's more than a few reasons they are being abandoned.
You can ignore the science all you want.
But you can't wish physics to change, and science doesn't care if you ignore it.