Also tabbed web browsing. I tend to line up the YouTube vids I want to watch while coffee brews, then watch with coffee in hand. Sometimes they get left there for the entire day, minimized while I do something more productive. At least with chromium, that takes a lot of memory (even though it does a few things to conserve). I also have a few other applications running all the time. It gets pretty close sometimes.
Anyway, now that they're available, I'm getting one. I sure have a lot of Pis nowadays.
One reason: your project is already designed around the RPi form factor, and/or you already take advantage of things like GPIO that are more specific to a Pi than a "mini PC" or whatever. And it would cost enough (in actual dollars, or just in time/energy/attention/etc) to redesign the project to where it makes more sense to just upgrade to the slightly more expensive Pi.
With 16gb you can have a massive file buffer cache and avoid disk io delay.