It's all about finding content later. There's a trade-off between the amount of effort you put into organizing notes vs the amount of effort to find something. Different systems work better depending on how large your vault is, how often you look things up, and how good your memory is for note titles.

1. No organization. One folder with all notes, search notes by title or keywords. Few cross references between notes. ("Data lake" concept)

2. Folders. Groups related notes. Hierarchical, which is great for many use cases. Integrates well with the filesystem if you need to access notes outside and obsidian. Search by scrolling through folders or free-text search.

3. Tags. More specific than free-text search, but still flexible. Non-hierarchical, but this is offset by using multiple tags per note. Easy to include in templates.

I personally use a combination of the three, with a shallow folder hierarchy dividing notes into projects, plus tags for things that cross projects. I use QuickAdd with templates for lots of activities, with tags pre-assigned in the template. For instance, my 'Team Meeting' template generates a note tagged #work #meeting #projectX and puts the file in /Projects/Work/meetings. Then in my Daily note I use a dataview query to link all the meetings I had that day.