It takes a lot of energy to pull CO2 from the air since it is only 400ppm. It also takes energy to make hydrocarbons. This means they will be really expensive. They might be used for classic cars but can’t replace fossil fuels.

Hydrogen or ammonia have advantages that can be made from water and nitrogen. Ammonia may be good for ships and planes since can be liquid at cold temps. But can’t substitute in cars.