My thoughts exactly, I can't really see someone not being able to charge their MBA within even 7 hours let alone 12 and on that point, who would be using the MBA for over 7 hours without being anywhere near a plug socket.
Well, as a consultant who just purchased a fully maxed-out 13" MBA today, I'll offer the following:
* Client sites mean moving from room to room, and building to building - not all rooms have outlets, and not all outlets are convenient.
* Clients like to sometimes have "working lunches" - also with minimal opportunity to plug in and recharge a laptop.
* My longest on-site day was about 11 hours, and keeping my current (non-Mac business) laptop alive was definitely an issue.
* Oh, and if you're at a conference that can go from 8am to the end of the regular work day, plus business meetings at dining establishments thereafter until 10pm, forget about getting to plug in for very long at all.
So, the portability factor with the MBA and the improvements in processor/graphics/flash storage speed are sufficient enough for me - I'm not doing serious photo editing or video work, but taking notes and doing Win8 with Parallels.
That said, I was a little disappointed that there was no 16GB BTO RAM option.