I genuinely do a lot of coding in Kate, the standard KDE editor. It's enough to do a lot of things, has highlighting, and is more than enough when you just need a quick fix.
I am also still using nano when editing stuff in the terminal. Please, don't judge me.
It also doesn't have Sessions.
Making it a better choice when you want to quickly open/create a file (the Session selection menu requires a lot of tabbing or using the mouse)
Yep, I came here to say that Kate is really nice. Even though I'm an emacs user and won't use it.
Nano, on the other hand, can't do almost anything, so I can't recommend that people make heavy use of it. It's ok for random small edits, but that's it. (By the way, YSK that you can set your terminal to use Kate as the default editor by setting the $EDITOR variable.)
But yeah, interesting list. These days, KWrite is basically just Kate with different configuration, if I understand correctly, so it always feels like you might as well go with Kate. In my opinion, KWrite is also not particularly easier to use, since basic editing works the same, but I guess, that can be disagreed on.
I do like that Kate is pre-installed. Imagine Windows, but rather than notepad.exe, you get Notepad++ out of the box. Now imagine that to also be a whole lot better and then that's what it feels like to have Kate on fresh installations.
You can just start coding something right away, without it being necessary to install a different editor.
Geany is a nice GUI option. It's a bit more capable but still lean.
It's probably time for me to re-evaluate the host of coding editors out there. For the most part I just use good text editors. Though I do love Spyder, I only use it for a certain subset of tasks.