A wanted ad made me think of this. The 67-70 Olds cruise setup does not have a "power switch" in the Cutlass circuit, power is on to the back side of the brake switch. In the 71 and 72, I think those years are right, there's a switch on the dash with a red bulb that sits in between the fuse panel and the brake switch. The 72 Chevrolet cruise also does not have this switch.

The control stick on the column is wired the same way, and both it and the brake switch work the same way, with a 3 position button on the stick being in, out, and mid, and it, along with tapping the brake pedal, controls the system. This extra dash switch on the 71-72 dashboard seems superfluous as it has the same function as being on the brake switch all the time.

Do people more informed than me know why such a switch was added to this GM division's A bodies and not other ones in these years?

 

I can't answer why Olds did that, but they kept that "tradition" for many years. My '80 Custom Cruiser had the dash switch. I agree it does seem redundant. I could be wrong but I think only Olds had the dash switch.