Replace "diamonds" with "any particular useless piece of junk".
For example, I ran out of gold, so it will take me forever to sleep off the 47 fatigue I got from being beaten nearly to death, using only my old, patched tent. But I do have these three crystal globes for which that merchant over there will give me 2 gold and 3 silver. I can either rest in my tent for 30 hours, or I can sell the orb, get a bath and massage, then spend 8 hours in a private room, and be back in business nearly 20 hours sooner.
Anyway, selling items is a way to get gold, which you can use to get more stuff to make your life easier, and reduce the down time associated with an advy. If you have the excess items to sell, the go for it. And buy better equipment, too, while you're at it. If not, then you can just sit there and enjoy the wait for your time pool to refresh so you can use the cheap/inefficient resting methods.
