It's portable (although it's not a feature I care that much about), but programmatic layers are a huge plus for me. I use Vim and now I don't need to move a hand off my home row to use arrows and I love this. So, it's not really about space. It's also aesthetically more pleasing which is subjective. I'm a bit of a minimalist. I refuse to use multiple monitors such that I don't get used to having the additional screen-space, because I do have a tendency to work at coffeeshops and my workflow remains the same in the office and outside of it.