File access is a complicated story in a Sandboxed world. I’ve explored different ways to incorporate direct file editing over the years, and never been satisfied I could deliver something that didn’t come with far too many trade offs.
By design, Drafts tried to eliminates a lot of the complexity of files and folders. That was part of it’s appeal - no need to create files, name things, decide where to put them, etc., just to type some text.
It would be difficult to create a way to incorporate direct editing that didn’t require significant compromises in how those files and their content were treated in actions and how they differed across sync between devices/platforms. Lots of issues.
Not saying it would never happen, but it’s not a focus for Drafts at this time. Just import-export for now.