@Steve has never said irregardless.
I'm not sure irregardless is even a word, but all cameras are computers now, you can pretty much assign a choice of several buttons to activate any function. The camera doesn't care what button you set to activate autofocus, it run the same program whether you assign it to the shutter button or to af-on or any other button within the allowable choices. In the manual for my Canon it shows 6 buttons that can be set to run AF and wake up the meter.