In H2 car the H2 is just a really inefficient battery. Sure it can hold a lot, but it loses a lot. You lose it in energy conversions (to H2 and from H2) and you have to transport the stuff, and it leaks (smallest element) and it has to be cooled and compressed.

Battery tech is getting all the time, and really, you only need 300 mile range (many have that now) as humans have to stop for a rest/wee. With a charge network like or petrol network, you can charge then.

Edit: English