I use it for pretty much everything. Any random crap i need to jot down go into the daily notes with a tag of some sort, Excalidraw extension for any sort of diagrams or a string board for connecting different notes/pictures together, code snippets, documentation etc.

I dont use their sync, but I have proton drive keeping the directory backed up in case of emergencies, and I have a git repo for when i want to officially keep something tracked.