I understand criticizing Apple for not including a USB-C cable in the box after pushing it so heavily on the MacBook / MacBook Pro, and the fact that most of Apple's competitors have embraced it, but the truth is that most of the USB ports in existence are still USB-A.
Existing chargers, in-car USB ports, even Apple's current-model Mac Pro from 2013 - all USB-A. I don't have a single device with USB-C yet. Would rather hang on to my 2012 Retina MacBook Pro with a built-in SD card slot and other more useful (to me) ports.
If they included a usb-c cable the ~90% of apple users that havent bought a new computer yet will get really angry...
And those 2012 ports are really absolutely not more useful