[diarmuid_glynn]

Right, the idea is you can use Sheet Markup to author interactive spreadsheets. Consumers of those interactive spreadsheets can then modify the data / formulas in the spreadsheet to perform ad-hoc analysis (which are not saved).

That said, I think 8n4vidtmkvmk has a point that it would be nice if when authoring the Sheet Markup, edits in the spreadsheet preview would be applied "in kind" to the Sheet Markup (bidirectional sync). This would mean you could author the Sheet Markup using the spreadsheet preview, instead of relying 100% on Sheet Markup for authoring.

[8n4vidtmkvmk]

Yes, there should be 2 modes of operation. One for authoring and one for consumers. This link looks like it's authoring because it has the markdown on the left. Viewing mode presumably wouldn't let me edit the markdown at all. In that mode, letting me tinker with the numbers and not have them save might be helpful. But I'd go one step further and add a "Make a copy" button under the sheet which exports the data into Google Sheets or downloads an CSV.