There is a passive ability that allows you to engage in non lethal combat.
You can loot knocked out characters but there is a separate on death script that can generate a significant amount of treasure.
As it stands killing a creature is far more profitable than knocking someone out.
I don't believe that was the intent of the non-lethal feature.
Yes. With vendors in particular this gives you access to all their vendor gold but only if you trade with them first. If not you only get standard loot table.
If you kill a vendor instead of knocking them out you get back everything you traded to them + standard loot table, but not the vendor gold.
After you loot them (when they have been knocked out) if you kill them you (sometimes) get access to a second standard loot table drop.
It has modified our player groups behavior in multiplayer when we are dealing with having to kill the vendor in the Toll Road for the Hunt the Devil sidequest for Karlach.
Outside of that - it's generally not convenient to do non-lethal damage in other situations, and we don't kill/attack the Hag because she is too valuable as a vendor.
