I feel as though there is a far more practical and intended use for this function.

As the reviewer has stated that he seems to find that the button is in an unnatural position to be pressed by the digitus minimus, I believe the original intention was for the player bind a survivability cool-down ability / macro to that specific mouse key so that in the unexpected event that you find yourself going 'oh shi-' and under the immediate effects of the flight-or-flight response and prone to 'flinching' as your muscles tense up, you should be able to train your body to 'flinch' the mouse immediately to the right side of your mousepad / desk to the secured brick that you have conveniently placed to perform the maneuver that will cause the digitus minimus to activate the otherwise normally considered 'ergonomically flawed' button due to the resulting collision between the brick and the mouse at high speed. This gives function to the otherwise immobile minor knuckle portion of the finger that seems to be responsible for the use of the mouse key and I believe this genius and thinking-out-of-the-box design should have received a lot more praise in the article.

It may have also been intended for people who use a tad more extreme 'claw grip' on their mouse, but that's hardly interesting.