[scubbo]

(For myself) because 99% of my time is spent in an IDE or a browser, and there's less mental overhead for me to open a new tab and start typing than for me to open a new app and do so.

[qalmakka]

The IDE is literally a text editor. Why not hit file -> new file and write stuff in there?

[cess11]

For me it's the risk of littering in a project repo.

So I use Zim wiki instead: https://zim-wiki.org/

[qalmakka]

AFAIK all editors and IDEs I've ever used can open a random file in a new tab, even if it is outside of the repository.

[scubbo]

Because "random human-language notes" are conceptually different from source code for me.