I actively use Obsidian and Notion.

Obsidian is very good for technical and static knowledge bases. I use their publish feature for my digital garden. Having local markdown files and working on them is great. Obsidian is basically a secret sauce over markdown file format.

On the other hand, dynamic content lives much better in Notion. Databases, formulae, interconnection between other services etc. makes it a great project management tool for my life. However, due to the file format and everything can be interconnected forms both a walled garden and moat at the same time.

Both serve different niches and work very differently. So neither one is a silver bullet by themselves for all scenarios.

But Obsidian is a great knowledge management tool if used right, that's true.