Interestingly my number #1 killer feature for N++ seems to be "having multiple unsaved files open and they are transparently saved and restored after restarting the app". In the past I've judged people who did this with a "just save your damn files" but since I, too, have converted to the ephemeral notes buffer where I don't want to find a location and file name to save it.
The funny thing is that my N++ instance has ~5 files always opened, 3-4 of those buffers and when they get to 6 or 7 I trim them down to 3-4. This is probably the beginning of why we find people doing weird things...
(I personally ditched n++ because the shell highlighting false-positives errors, and syntax errors are especially ugly in the default scheme. And it wasn't on GitHub back then, so complaining would be a chore.)