I'd agree, sil, for black / grey box. One semi-exception - same exception for which I'm getting mine. White box testing, where I'm tasked to see from the insiders' perspectives. Yeah, I could deploy a laptop or machine, etc, but cheaper (shipping, if remote) and easier to just have them plug in a pwnie for me, and go about my business.
But again, I fully agree with you on the rest. Just that there are times the little units do come in handy. Believe it or not, I easily deployed a similarly 'modified' unit (non-pwnie, but another vendor's outlet pc, with my added code - and no, I don't work for pwnie) in a hospital, in a paid, black box test, too. Amazing how easy to slap one in a spare network jack under a desk at the check-out / release desk, when they turn their back or go to the printer... ;-). I have another similar gig coming up, so looking forward to testing out a real pwnie for this one.
~ hayabusa ~
"All men can see these tactics whereby I conquer, but what none can see is the strategy out of which victory is evolved." - Sun Tzu, 'The Art of War'
OSCE, OSCP , GPEN, C|EH