Any carbon-based fuel ultimately depends on a lot of capture infrastructure to be carbon-neutral. In the short term, it's hard to see a path to viability. Ammonia is easy to synthesize, ingredients are literally water and air, liquefies at achievable pressure, and can be directly consumed in a fuel cell or combustion engine. It's corrosive, but only to certain materials (late transition metals and aluminum), and toxic, but only in high concentrations (the body naturally contains a few ppm of ammonia at all times). It's biodegradable, so you don't worry as much about spills. It's flammable, but not extremely so like hydrogen.