Where does the hydrogen come from? There is just about no free hydrogen just sitting out in the environment, so the hydrogen has to come from using some energy to split its atoms from some other chemical compound. It would be more efficient to use just about any of those energy sources directly rather than having a energy->hydrogen->energy stage wasting some of the energy. Some arguments could be made for having hydrogen powered vehicles when the original energy supply is not portable, and possibly for solar panels to split water into hydrogen and oxygen to be used at night.
I think most hydrogen used industrially comes from cracking methane in natural gas, but for a energy source it would be far better to just burn the natural gas rather than turn it into hydrogen.
Why don’t just burn water. I mean it’s like, you know, H2O. What burns better than hydrogen and water, man? Of course, what we gonna do with all the ashes?