Ammonia is significantly more harmful in the event of a leak. Yes, it’s more hydrogen dense than pure liquid hydrogen.
Ultimately I don’t see a reason to dismiss hydrogen like some are doing. Is it the perfect solution in all cases? Of course not. Does that mean it is not a viable fuel source for transport? Absolutely not.
Scale solves most problems. Hydrogen also has other uses, such as steel production, which further increases the scale.
For light vehicles batter EV is likely to be the leading type for some time, as volume is more of an issue then weight for the ranges we need.