It also means the difficulty ramp for the game is far less steep, as you can blitz through on novice, then change up to skilled and then, eventually elite. The medals look different for each difficulty, so you can clearly see on which mode you've completed each task. This doesn't help with the most difficult trophies, but at least completing the game is actually possible for normal humans. So, if you haven't played WipEout HD for a while, give it another go. You might get sucked in all over again -- we certainly did.
[Thanks to everyone who sent this in]