Markdown is lovely to write in and awkward to hand over.
It is the best way to write something long. Then you finish, and the person waiting wants Word, or a PDF, or something their e‑reader will open - and there you are, pasting an unpublished manuscript into a website you have never heard of.
That's where Bindery is. Point it at a file or a folder, choose a format, and out comes the document - contents page that navigates, diagrams drawn, equations typeset, code still coloured.