The one thing I wish this tool had is the ability to tap on touch screens - coffee shop cash register screens, grocery stores, mail lockers, etc.

So the thing you put in your pocket with your hand has touched the door or button? That seems fairly not useful.

I figured it would at least have some sort of retraction mechanism that would hide the piece that touched the public surface.

the first time you have to go through a metal detector / entry search - this will be thrown away due to looking like brass knuckles.

How do you open doorknobs? That's the one I have an issue with.