The Air is my private machine and I bought for size/form factor (aka travel).

I had a MacBook Pro 15" (far better spec'd) at the time, but left it at home/work due to size and weight. The 11" Air fits "everywhere" and still has a full size keyboard and a good trackpad.

My Late 2013 MacBook Pro (bought early 2014) is a 2,3GhZ i7, 16GB memory and 500GB SSD. Compiling, VirtualBox/Parallels and Docker is less painful, but 99% of the time the old 11" Air is good enough.