[attasi]

This is something we are constantly exploring. They are in fact the same under the hood but it’s been a tricky UX challenge to provide a seamless and intuitive way to toggle between the two. Always thinking about this though. Have any thoughts on it?

[deejaybog]

A Document is not the same as a Surface, it is a special case of Surface with formatting and positioning restrictions. So while you could "toggle" from Document to Surface, it can't be done the other way around without losing spatial placement information.

The landing page says "Write, sketch, and embed on an infinite canvas." Why not stick to the promise? I'll reiterate my suggestion: make all pages infinite and remove Document as a "root" page style. Its functionality can be exposed as a "rich text" block.