Synology Drive is a file and folder syncing system.

Obsidian is a note and wiki syncing system.

You should use an obsidian syncing system if you want to sync notes and wikis. You should use a file syncing system if you want to sync files.

This reply does not address parents question at all.

A key feature of Obsidian is that it stores your notes in an open folder structure on your file system.

A very valid question is whether there are benefits to using a special note sync application rather than a standard file system sync application, and if so, what those benefits are.