I know that going from a 2015 Macbook Pro to a 2017 one made a gigantic difference in how I used the device. The 2015 one I had to decide if I wanted to put in my backpack. It added a non significant weight to my bag and therefore my back. I wouldn't open it while standing or outside, simply because it wasn't comfortable to hold in one hand, or to type in a password.
The 2017 Macbook Pro, while flawed in many ways, is very different. I carry it everywhere without a thought. I can easily carry it open in one hand or closed like a book. I can pop it open for a second, type some stuff in while holding it, then put it back (TouchID is great for this too).
This may sound like Ive-esque purple prose, but truly, a lighter laptop lowers the barriers between the physical object and what I want to accomplish. I don't have to think about the physical weight of the laptop. I can just bring it. I don't have to think about putting the laptop down and using it. I can just palm it.