Obsidian must be open in order to make edits, so it doesn’t matter if Obsidian can or cannot open markdown files.
Obsidian stores files in an open “database”, so it knows where to search for all its markdown files
Maybe Obsidian could import / move outside markdown files but then, into which vault? The current one if a vault is open or yet another vault if Obsidian is closed and you’ve more vaults?
Obsidian handles files based on their open database concept called vault. It’s not about markdown but knowledge management inside an open database.