Doesn't matter how old it is if it is the truth. Truth stays true. That is why Archimedes's tomb had Calculus on it way back when, and we use calculus now to program out machines. Truth doesn't change over the ages, unless something to do with that truth changes. Since we are still sleeping the exact same way as we were when it was made, then it still applies. We aren't all cryogenically frozen every night instead of just sleeping.

My favorite parts were creative problem solving, using it for art, and adventure (I think it called it wish fulfilment, like going to different universes in your head).