> For comparison an EV can do about 400km on the same energy.
I checked prices here in Norway. My car has a 60 kWh battery and my car can indeed do about 400 km when full. Hydrogen here goes for about 195 NOK/kg at the pumps, so 4 kg would be 780 NOK.
Even if I use an expensive super-charger to charge it up fully, at ~6.5 NOK/kWh it'll cost me 390 NOK. So half the price of H2.
Tesla super-chargers are now available for regular plebs and they charge about 5.5 NOK/kWh, and there's at least one other that charges around 4.5 NOK/kWh.
If I charge at home it's typically 0.8-1.2 NOK/kWh during summer, up to 2-3 NOK/kWh during winter. Since I have this option, I only use super-chargers a few times a year, when on longer trips.