Ammonia production for fertilizer is the second largest use of industrial hydrogen today after oil refining. About a fifth of the hydrogen produced today ends up as ammonia. Ammonia has advantages over hydrogen as an energy carrier in that it can be stored and transported as a liquid with a higher energy density than hydrogen. Converting hydrogen to ammonia is a technology that is more than a century old, but it does entail additional capital investments and energy losses. Ammonia is also toxic in relatively low concentrations (hydrogen is not). So there are definitely pros and cons. It is definitely a contender for the storage and transportation of hydrogen. Certainly using hydrogen produced using renewable electricity is the only viable means of electrifying the manufacture of ammonia today, so the future of it is relatively bright.