The MBA is 36% heavier than the MB. For some people minimum weight matters.I still don’t understand what the point of having both the MB and MBA is now, especially since they haven’t updated the former.
The only way to justify it going forward is to treat it as a testbed for Apple’s own processors being used in the fanless MB. Make it an ultra sleek, significantly higher battery life version of the previous gen while at the same time laying down the groundwork for transitioning to full on Catalyst apps and basic x86 emulation. (The people buying this A-series MB aren’t going to be running advanced x86 apps anyway.)