Okay, so, I would like to approach this from a purely game-based point of view, detached from any moral/ethical considerations.
With the "what you see is what you get" idea of inventory and harvesting (really cool mechanic, btw), you could easily subdivide the humann body into cosmetic and mechanical components.
Cosmetic components might be the head, ears or fingers which act as identifiable markers of the person being butchered. These could be important for verifying the permadeath of a specific individual, creating totems (head on a pike) for display that might carry mechanical effects based on fame/infamy, or some other unexplored purpose.
Mechanical components might be the skin, meat, offal, and bones of the person being butchered. All four components, particularly the meat, could be used in crafting. The skin could be used to create profane armor, equipment (fleshbound tome for liches to write their dark machinations in), or even disguises. The meat could be used to either feed a starving and desperate population during a prolonged world event, be consumed ritualistically to either debase one's recently deceased enemy or venerate one's recently deceased ally, or used to craft special consumable items with variable effects. The offal and bones could be used in crafting or building projects, or they could be buried in order to put a soul to rest (perhaps your soul takes a penalty if your previous body was not properly put to rest).
We know you will be able to place bodies on carts to haul away, but it is unclear if this is simply KO'd bodies or limited to only permadeath bodies. It would make more sense if butchering bodies was limited to permadeath bodies, but I strongly believe KO'd bodies should be able to be moved, even though this probably interferes with the soulwalk mechanic. These parts would probably be outlawed in most kingdoms, creating a blackmarket to meet the demand for their purchase. All of this leads to interesting gameplay possibilities, so I am 100% for butchering humanoid corpses and, thus, cannibalism being a thing in CoE.