As I mentioned earlier, my spike camps or bivy camps are not my typical camp. That's only for special circumstances like being close to elk at the end of the day and miles from base camp, or if a big storm rolls in quickly. You've got to carry a way to stay relatively dry and warm overnight. It's not for extended periods, and it's not high comfort. That's what base camp is for, and my base camps are very comfortable. Not too far from the truck, nice canvas wall tent, cot, big thick sleeping pad, big thick sleeping bag, heater in the tent, ample cooking setup, plenty of water, food coolers, a little bit of whiskey, etc.
If I'm not on top of elk that I want to hunt at daybreak, then I'm heading back to the comforts of base camp even if I get there after dark. But if I've spent the day chasing elk, and it's almost dark and I'm 5 miles from base camp, I'm going to spend the night where I am. Elk hunting is all about creating opportunities and if I'm on them I'm going to stick with them until I can get it done. No matter what, comfort be damned.