I use VS Code most of the time, but the reason I always use Notepad for taking quick notes _is_ the startup time of VS Code. If they improved it, I'd be using it for both. It is an important metric for some.
I work in IntelliJ IDEA whise startup times are horrible. However, since I always work on a set of projects, I never close them, so, essentially, startup time is 0.
Also, IDEA has scratch files for quick notes available through a shortcut (I guess VS Code might have a similar plugin), so startup tome isn’t an issue either.
Still get syntax highlighting and everything, but waiting for VS Code can be long enough to derail my train of thought.