I hadn’t thought of this. Good call! A possible downside is that unfortunately you lose the backlink functionality when embedding in canvases. And, in the long term, it can be a bit tedious to draft and rearrange within canvas. The issue with generating an output would also be annoying. There are threads about outputting canvases such as this: Convert Canvas to note(s) (enable the use of Canvas to initially outline long-form writing).
And I just created this request: Alt drag and drop multiple selected nodes in canvas to generate sequenced list of links. This request is also relevant in that respect: Note Combination.
But, you are absolutely right. When you want to be able to easily edit embeds from various sources, arranging them in a canvas can be a pretty good workaround.
Thanks!