The Macbooks that were for many years the smallest and lightest Apple laptops, would be imbalanced and knocked off your lap by placing your hands on it slightly asymmetrically.
If a laptop is too thin and doesn't have weights in it, just having it in your lap while lightly typing makes it wobble around like a boat in a storm.
I think these super thin laptops are ugly, too hot and not ergonomic - also this sacrifices the keyboard. I actually think this model represents the perfect mix of all of these things - thickness (being the thinnest thing I can buy is not a feature for me) - weight (I really don't mind 1.3kg) and keyboard.