The problem with hydrogen is that it is used to power piston engines. These are fundamentally inefficient due to the pistons having to stop and start twice with each complete stroke. Rotating electric motors have up to 90% efficiency and somewhere about 60% in a car. This compares to about 20% for petrol. How efficient is a hydrogen powered piston engine??

https://www.fueleconomy.gov/feg/evtech.shtml