Prophetic is developing technology to induce lucid dreams, in which CEOs can practice for board meetings and architects can design buildings while asleep.
Third comment in this post about this from me, but I've done university work while lucid dreaming, solved bugs we didn't even know existed, stuff like that. I don't think you rest as much while lucid dreaming, I'm pretty sure I built up fatigue at many points in my life just due to how much lucid dreaming I was doing. I now avoid lucid dreaming, and have started losing the ability to do it frequently (which frankly is a blessing). I feel more well rested now than I did when I lucid dreamt a lot. No way this idea doesn't just leave you completely tired after a while.