Sure, but if you want hydrogen in order to burn it wit oxygen and make heat and water in large scale then getting hydrogen from water is obviously not an option because of thermodynamics 101.
If you need hydrogen for something else, or if you need it to burn it with oxygen in some special application (e.g. rocket propulsion), then it may an option.
Not even all that high—water is pretty common...
Basically, the price of energy to split water into oxygen and hydrogen is a hard ceiling for the price of hydrogen.
Sure, but if you want hydrogen in order to burn it wit oxygen and make heat and water in large scale then getting hydrogen from water is obviously not an option because of thermodynamics 101.
If you need hydrogen for something else, or if you need it to burn it with oxygen in some special application (e.g. rocket propulsion), then it may an option.
It is a perfectly good option if you need hydrogen as energy carrier and not as energy source.