For those times when it's warm enough for the choke to be open but the engine isn't cold enough to set the high idle for one.
It seems I'm always opening the hood to set the high idle up in the mornings and I don't want to add choke doing it.
One other main reason is I like my in gear idle to be higher but not keep it that high when in neutral.
The Holley high idle cam is technically physically separate from the choke, but I would still have to pop the hood to set it up on the first step of the idle cam.
Most wouldn't pay it much mind, but I'm kinda strange like that.:D
