It seems to me that an iPad + keyboard would weigh about as much as a Macbook Air 11", would be about as thick, if not thicker in some cases, than a Macbook Air, and would cost about as much total as a Macbook Air. Yet, it won't be able to run 2 or more apps side by side.
I like iPads; but I don't understand why anyone would prefer this keyboard + iPad route over a proper laptop.
A $500 iPad Air plus a $100 keyboard is still cheaper than a Macbook Air.
That aside, the real reason I prefer an iPad + keyboard set up is the usefulness of the apps. I debated iPad Air vs Macbook Air and the iPad won out for my needs. Your needs may vary, but don't treat people who use technology differently like they're stupid.