I like the general concept of sandboxing applications, but if it leads to this, it's more hindering than helping.
Personally, I was hoping TextBundle would be something like a standard format for inserting binary content into Markdown files. (Something better than just base64, anywho.) I could use such a thing for my home-grown wiki.
Sure, I can zip everything and send them over, but it's not as friendly for recepient as receiving a document handled by popular viewers, specially if they have to modify it and send it back.
With wide adoption of something like TextBundle, we get to have our cake (keep using plain text) and eat it too (send, view, and edit richer files).
solves this one issue at least
I use markdown for personal notes and in the rare case I shared them in the past, either there were no (relevant) links or I shared with e.g. confluence and I could just add the image.
My other usecase for markdown is Readmes and those are shared in git including the files.
I understood this spec mostly for sharing with local apps. Is that a missed usecase by me? Markdown documents instead of word/pdf/powerpoint/whatnot?
In particular, if you attach a file to a note in obsidian then no other program can link to the right attachment, right?
Your directory has note.md and image.jpg. The note has a link to the image. The client can then render the markdown and image as it wants.
Any other application can also find and link to the attachment because...it's a file.
Most recently I tested this with obsidian, ia writer, obsidian.nvim, fsnotes, and a few others I forget the name of.
Especially if you want to access your notes on mobile and have a good syncing experience... you're out of luck if you want a non-proprietary format. Only notion and apple notes had reliable syncing.