If it actually is that inexpensive then it would cost less than gasoline for equivalent energy output.
Prediction: since the whole "Climate Change" nonsense is politically (rather than scientifically) motivated, the Usual Suspects® will start coming up with reasons that this is bad for the environment. My guess is that they will say that burning hydrogen produces water vapor (true) which is the most prevalent greenhouse gas, responsible for ~ 80% of the greenhouse warming (also true). So they will claim that water is a pollutant, just like they claim that carbon dioxide is a pollutant. I mean, the economy isn't going to change itself into a Grand Socialist Experiment, so they need something to complain about.