With so much negative response, it's as if nobody had to adjust
a rangefinder for proper focusing. I wish my zeiss sonnar had an
option like this for focus shift at different apertures.  You
don't have to use it.  But some people use AF cameras. Some
people use them with 3rd party lenses. Because the communication
is digital, a number of older sigma lenses don't work on newer
bodies and have issues.  So, considering that a camera becomes a
complex system of the lens computer talking to a camera
computer, it only makes sense to update the lens computer.  I
love manual focus camera to death, but in normal light my AF
SLRs focused faster and more accurately than any MF camera. And
they do it off center as well. And they also track moving
objects.