Silly me, it has taken me almost 20 years to realize that the hinges of the Metal Zone pedal are screws that can be removed.
Well, in my defense I'll argue that actually, that fact wasn't very important until a few years ago. The pedal started its life as a device mostly used in concerts, i.e. meant to be kicked, so there was no need to remove the structure.
But as my focus of possibilities has turned more to the field of recording, pressing that huge bulky thing every time I wanted to turn distortion or on off was an absurd and dirty overkill (you can see the spring a bit in the right side picture - really resistant, lots of toil for a hand to handle).
This is a classic case of the waste called Movement: motion (or effort in this case) that does not add value. If you can switch distortion on and off by pressing a little nifty button, any other strength used in excess of that is waste, energy that has a cost but does not go into the quality of the final product.
The location of the pedal is also strategical: standing vertical on the table, so that all the controls are visible, and, although you can't see it in the picture, close to the sound card, so all the knobs are together in one place and easy to reach, all of which reduces motion too.