Since everything you ever read is stored in your subconscious somewhere, couldnt you theoretically use LDing to study for tests? Literally both Pull an 'all-nighter' and get lots of sleep? And if you can control time you could study for a test for hours. If you were studying history you could use what you know to place yourself in a big battle in the Civil war or something.

I dont know exactly how this would work (or even if it would work at all because its hard to read in dreams), but does it sound like something you could do?