How good an idea is this, really?

Assuming that there actually is something to this, what would that mean, exactly? Yes, there's a lot of salt water on earth, but we've never quite figured out how to make water, or how to destroy it, for that matter. This looks like it does the latter and forces the question, is it really a good idea to separate water into its component parts, hydrogen and oxygen, for energy? Of course the notion that we can destroy water begs a serious Oh really?