Hydrogen has huge practical problems with storage. Ammonia is an interesting idea, but direct combustion isn't practical due to NOx emissions and low temperature, and ammonia fuel cells are still at the lab prototype stage. The toxicity of ammonia is also an issue.

It is carbon neutral to make hydrocarbons and then burn then as long as the energy source for making them is carbon neutral. The hydrocarbons have the advantage of far higher energy density, which makes them much better as fuels.

More energy efficient maybe. But I'd much prefer a city where every of the (hopefully few) car/scooter engines is either electric, or the exhaust spews water vapor.

Plugin hybrids would solve a lot of this problem. Battery can be ten times smaller and no range anxiety for much of the same benefits as fully electric