Using your phone as a boarding pass -- bad ergonomics

I've been meaning to write something about this for a while, but since yesterday I used my phone for a boarding pass again and ...

I'm not really sure it's a great idea.  Mostly because, well, when I'm traveling I'm clumsy.  I have a suit case, I have a brief case, and when I'm going through security I have a driver's license out and, either a boarding pass or my iPhone.  That's a lot of moving pieces.

The iPhone is getting moved around and waved around, and that makes me nervous.  It's an expensive piece of hardware to have in motion when I'm juggling other things.

A piece of paper and a driver's license are easy to handle in one hand, and they go to the same place, the TSA agent.  The iPhone and the license are going two different places.  That's just bad design.

As a side note, since they don't appear to look at the phone, and the scanner device doesn't appear to show my name (did I miss it), what's the point of showing the license? (Not that there ever really was a point).