One is for work, one is for personal projects and notes.
One for Books and Movies I watched or want to watch.
And one for Zettelkasten[0].
Obsidian is extremely customizable and user-friendly. And to make things even better, which is a must for many people including me, it saves the files as .md in the local storage.
You can even sync it among n devices for free using Box, Sync, Mega, OneDrive, Dropbox or whatever floats your boat.
Just as a quick exercise, I spun up a fully functional Obsidian clone that runs in the browser that works locally, in four hours using React- just in case the company goes under in future. It works great.