We have lives outside of work that also helps informs our opinions on these things.
You would, provided that MacBook Air had convertible screen (like Lenovo Yoga)
Obviously the same use cases for both products!
The tablet form factor (with a larger screen) does offer a compelling use case for drawing and other art, but in general the tools available are inferior to software available for Mac OSX and Windows. This is where the Surface makes a lot of sense since I can draw/design on the go while having access to best in class software.
I'm not a Windows user, but it is for this very reason that I keep thinking of buying a Surface; it's gotten some great reviews from other artists/designers.
I also find it discouraging that Apple has introduced their "revolutionary" new Pencil at a $100 price point, but I can't find specs anywhere, and I know I can buy the Wacom Creative Stylus 2 for less money and it has 2048 pressure level sensitivity. Without published specifications it leaves me wondering if the Apple Pencil is less product for more money.
For a device at that size, weight, and cost you would be better served buying a Macbook Air.
Apple has dozens of devices for dozens of use cases and types of buyers. I would never use the new MacBook (not good enough specs), and most of HN thinks it's a terrible idea. But my wife loves it. She doesn't need to run a virtual machine or plug in i/o devices or use 16GB of RAM, and it helps her do what she does better than ever.
If you look at Apple keynotes through the lens of, "Will this product change my life?" you'll likely be frequently disappointed - they're building products for a wide spectrum of users. But every now and then, they'll likely absolutely nail what you need.
If you buy a Macbook Pro when you need a laptop, it doesn't matter if the Macbook Air isn't for you. Apple still wins.