Too volatile. Too small of a molecule.
Ever see an explosion resulting from a hydrogen leak?
I have, and it was only “minor”. Lofted a 400 lb. retort cover 40 feet up until it hit the roof supports, and bent them about 6 inches. It missed the furnace operator when it came back down, thankfully.
If a neighbor started parking a hydrogen car in his garage, I’d sell up and move ASAP.