Because it is fun. Otherwise there is no other reason. I don’t see a problem with that. My first char had stromvauld mine elite before there was favor in game. It was not for exp there was far better ways to get that. It was not for loot south 3, co6 or tempest would have been much better choices for that. It was just for fun.
Is it really that hard to find quests of the correct level for you that you need to run the same quest for 3 levels in a row?
Only level that I can thing of that it pretty much impossible to level up doing quests of your level on normal is 15-16 since there 2 level 15 quests in game only. That should be fixed but changing difficulty to do level 13-14 quests on hard/elite I would find a very disappointing solution.
Because quest level is what level the quest is design for and difficulty should be how hard the quest is for people of that level. I view them as completely different things.Why do we not have "choose your quest level = choose your difficulty?"
Even in pnp I considered some campaigns design for let say 4-8 more difficult then another campaign design for 4-8.