I may underestimate the value of gold from mobs... but for me they tend to be a very small portion of the wealth I make, most of it comes from selling items so I wouldn't dream of hurting survivability for it. And taking an item slot to do it... As far as xp you normally don't have troubles capping heroes in a chapter anyway.
Also aren't the honor store items better for this function anyway.
But I am interested to hear what others think.