Yes, but support for showing the Markdown version is much more widespread. observablehq puts Markdown in JavaScript code. I think it works better with Markdow

Yes, but support for showing the Markdown version is much more widespread. observablehq puts Markdown in JavaScript code. I think it works better with Markdown even if it wasn't supported in multiple places, but since it does, I think having Markdown be the container format is a clear winner. There is also MDX but I prefer stuff that displays in the rendered view as well as in the source. Of course the renderers can change, but that's slow. As for inverting them without losing the data, that seems possible and would be interesting to see.