I dont know, one is basically more put or has designed around the interest of use and the other has more interests of use, you decide for the pick and wait to see if there is any difference. Or try to find the info for your own interest.
Maybe more like, is having a mouse going through a keyboard any faster then going through its own "port" for either?
Still, think it would be debatable many times over.
See theres, all sorts of USBs, yes? Mouse may have more buttons at times, then scroll wheel and trackball.
Keyboards have many buttons, and some with buttons with more then one function with use. Then multi-function buttons within one use. Think some mice do as well, too.
Some keyboards can have a mouse be plugged in, if i remember right.