1) where would you place the volume buttons? keep in mind that the front and back faces are not going to work unless you add significant thickness and another circuit board to the design. The board itself is EXTREMELY densely populated, and the only other way you could add the button is to increase the size of the device to make room. Then you'd have the buttons on a rather long riser, which reduces durability and increases the likelihood of damage. It also makes repair/refurbishing very difficult since now you have to try soldering in the middle of a bunch of other components.
The volume buttons IMO are perfectly placed for use with a shirt clip. The device clips to the front neck of your shirt, you make a U shape with your thumb/forefinger to reach up and interact with it. This provides finger/thumb operation to every button you could possibly be interacting with regularly. You cant put things on the bottom, there is a USB charging port there. You can put additional buttons on the top. The only thing I'd have placed differently is putting the microphone on the top, pointing at the user's face. And they probably didnt do that to prevent it from picking up hardcore breathing noises and chin/beard rustling sounds.
Dunno if you can see it, but here's what the circuit board looks like:
https://scontent-ort2-2.xx.fbcdn.ne...=d48bcbd3a89363c0108cae6d93a156d1&oe=5C10AF78
.