At a certain point it's not like it matters. If you're working for 5 hours, let alone 10, you will almost certainly be able to plug in during that time.
It’s true for me. I need a portable workstation more than a mobile laptop, as long as it survives train travels (most have power outlets now), moving between buildings/rooms or the occasional meeting with a customer +presentation it is enough for me.
But I can imagine some people have different needs and may not have access to (enough) power outlets. Some meeting/conference rooms had only a handful outlets for dozens of people. Definitely nice to survive light office work for a full working day.
