Most keyboards have a rectangular Return (often labeled Enter) key. Above it they have the \ key and above that is a rectangular Backspace key.
Some keyboards, however, have a weird shaped Return key that covers the usual position for the \ key above it, as seen below.
To place the \ key elsewhere, they take up space from the Backspace key. It doesn't seem like it would be an easier place to hit the button in its upward extension. Furthermore, backspace is one of the most commonly used keys on a keyboard and shortening the button makes it even harder to reach.
Why are some keyboards commonly designed with this extended Return key?