System76 laptops aren't known for their amazing battery life. The new(ish) Galago UltraPro supposedly only lasts 4 hours. Fine if you're plugged in all the time, but then why do you want a laptop?
I travel between countries a lot, and I can see myself doing that more for the near future. Being able to have just one machine -- rather a powerful desktop workstation and an ultraportable (like the MBA), is one reason I've been considering getting a desktop replacement laptop.
You get to take you work with you, anywhere. It's the alternative I've been considering, if I choose not to go for an MBA.
I sit on my couch with my laptop plugged in all the time. Am I doing it wrong?