Burning hydrocarbons produce their own problems, even if the source of those hydrocarbons is carbon-neutral. Soot, NOx, even unburned vapour are all not-great-things health-wise.
Also, if we get FF, then the possibility of relatively compact generation makes the current existence of a liquid fuel distribution system rather moot, as your source of motive power can be located anywhere, without any need to hook into a larger distribution system. (Indeed, the military may be the first to go largely electric, as it is far cheaper to plop down a shipping-container-sized FF generator than ship in tons of fuel or build a hydrocarbon generator that requires a lot of water.)
