And the hydrogen blew up. The United States which pretty much had the monopoly on the less flammable helium was prohibiting sales of it to Nazi Germany because of it’s treatment of German Jews. I don’t want a hydrogen car. I’ll stick with gasoline. And besides you still need lubricating oil under the hood and that means petroleum.
Once the dirigible started on fire, it is true the hydrogen also caught fire, but if the dirigible hadn’t been flammable then it is likely the hydrogen would have just went into the atmosphere.