I can let my agent edit those files all the same + there's better integrations and knowledge readily available on these.
I can tell my agent to edit the Obsidian Markdown just like that, but I can also tell it to create a full-on notebook with backlinks and DataView queries. I can tell my agent to create logically complex .org notes with code blocks and references.
To me, Hubble just seems like a Markdown editor, based on the premise that agents are able to edit local files.