I think he's immediately off track with his title - "Understanding good vs bad desires." He explains the general principle to some degree, but the larger point is that desires are not good and bad in themselves, only in the consequences in terms of pleasure and pain that they bring. So he ends up defaulting to the standard "live simply" result without really making any progress in understanding the larger issues as to why simplicity is often (but not always) the best choice. If you start off thinking that anything can be good or bad in itself without reference to pleasure and pain, you've given up the game before you start.