The problem with hydrogen powered vehicles is how you store and distribute so a technology to make hydrogen when you need it is good. It doesn’t sound like it’s low cost. You are effectively “burning” aluminium - the energy required to make the hydrogen comes from the oxidation of metallic aluminium to Al(III). If we had lots of waste aluminium that might be fine, but aluminium can and should be recycled back into new aluminium cans. This is quite a cheap process whereas to make new aluminium from bauxite ore requires a lot of electricity. This is why aluminium comes from Canada and the smelting plants are built next to hydroelectric dams.