I was a decky on a commercial boat in Alaska back in the early 80's, and using humpys for bait was common practice.
They were cheap and easy to come by, therefor making good bait.One squid, one bait. one humpy, (steelhead) ? baits.
And as far as only using jigs only for butts, I can't tell you how many we've caught over the years bragging a hearing around in 60' to 120'while king fishing(when you used to be able to that is).