Haha, yep, something about charging a battery with a battery just seems inefficient. Battery charging is never 100% efficient. Neither is discharge. From the point power leaves the wall outlet, getting the phone battery charged involves charging the power brick, and then discharging it before phone batt is charged. A complete charge and a discharge cycle just getting the energy to your handset. Possibly as much as 20 to 50+% loss! Multiply that inefficiency by 100s of M of users worldwide and I'm really shocked Al Gore isn't scolding us about it. Excepting himself, of course. Lol.
On top of that, I have several handsets staring at me from my desk rejecting heat from their Qi charge pods. AND that heat must be extracted from the building via HVAC. More non-green nonsense our charge contact equipped 9900s can't be blamed for... lol.
Like I said, tho, I do frequently carry a charge pod for my Classic, or what ever embedded battery nonsense I'm carrying. I DO use it on my 9900 when batt is getting low, mid call. It can be plugged in to prolong endurance without interrupting the call. Otherwise, after the second low batt warning, I simply tell the caller i'll call them back in three minutes. Swap in a fresh JM1 (or Monster) and call them back 3 minutes later. Typically within an impressive few seconds of three minutes. Lol. We're both usually grateful for the break. Lol.