There are two distinct reward paths in the game.
The first is experience points.
The second is loot, which includes wealth, equipment and crafting materials.
Combat rewards the player with the second reward path, and sometimes the first (if it is an important battle).
Quests reward the player with the first reward path, and sometimes the second (If there is a physical quest reward from an NPC).
It's pretty cut and dry, and it's clear to me that Obsidian has made the right call.