The large percentage of the viewfinder covered by Canon EOS 7D Mark II
AF system is a big deal, at least when shooting in AI Servo AF mode and when there is no time to recompose after focusing. The image shared with this post shows such an example.
The horse gallops toward the camera at perhaps 35-40 mph (56-64 kph). I want the rider to be in focus, but the horse's ears and mane strongly compete for the top AF point's attention as the animal quickly moves up and down. Having an AF point so close to the border of the frame allows me to (better) avoid the AF point's attention moving from the rider to the horse.
Good examples of situations requiring a wide-positioned AF point include any sports that involve running (track, baseball, soccer, football, field hockey, etc.). When a person is running fast, they lean forward and the head leads the lean. If the subject's eyes are not in focus, the shot is likely a throw-away. To keep the runner's eyes in focus requires an AF point placed on them and at the oft-desired near-frame-filling distances, an AF point positioned close to the frame edge is required. The 7D II has you covered here.
Cameras with a lower percentage of the viewfinder covered by AF points require similar subjects to be captured from a longer distance and/or with a wider focal length, meaning cropping is required to achieve the same desired frame-filling result. Cropping of course reduces final image resolution. The Canon EOS 7D Mark II's wide area AF system has you covered in these situations, allowing you to fully utilize its 20.2 MP sensor – this capability is a big deal.