Serious question: what are super-large laptop screens good for?

If I'm using my laptop on the go, I prefer a small screen so it's usable on a small plane tray, on a cramped cafe table, in a conference room where I don't want my device to distract, etc. And weighs as little as possible.

While if I'm using my laptop for real work, at work or at home, I want to plug it into an actual large screen, which 15" or 16" is not -- it's just too small. Let's do 25" or 30".

Large laptop screens are this weird middle ground for me that seem to be worst-of-both-worlds.

What am I missing?