I think the significant damage we can do to fats is in overheating them, if we render them but not to the point that they are smoking, I find any heat-induced change to acceptable.

I have no doubt the pemmican made with suet is better.  it's just that enough ordinary rendered beef fat for a batch of pemmican is available fresh on an almost daily basis in my house.

I would speculate that a hunter gather cook, having a whole hoofed mammal on hand to prepare for long term storage, would need more fat than just the suet, too.  But of course how much would be made into pemmican in relation to how much dried for simple jerky and how much eten fresh would depend on a variety of factors.

BTW I was found a 3 year old baggie of pemmican fallen behind something else in my pantry and its appearance and taste were as good as new.

Kathleen