I actually used a web text editor when I did Nanowrimo one year. It was great because I could use any computer (desktop, laptop, even my phone) and just type. I didn’t need any fancy tools, and performance wasn’t a concern because I wrote scenes in separate documents.
So I totally get it.
That said, I almost never use these apps for quick notes. I forget the URL, don’t feel like looking up a bookmark, etc. I’m a vim user normally, so I just open a terminal with vim. It’s great, and it works on all my machines (macOS for work and Linux at home), with the huge exception being my phone, but I have a simple notepad app for that (great for meeting notes, grocery lists, etc). But if you like a notepad, I’m sure you could keep the tab pinned and make good use of it.