Hi,
I can give my technical opinion.
At the moment the embedding functionality is limited to the map because the map shared is usually small (typically in an iframe inside a page) and so having the widgets upon a small map could be annoying. Moreover, to make the map load faster, the embedded version of the map has a minimal bundle with only the necessary to show the map, not including the chart library or any other plugin not necessary for the map.
I think that sharing dashboard could be more functional and useful, but it's my opinion. Embedded dashboard should not include top or left bar (like now if you include the row dashboard into an iframe.
https://jsfiddle.net/offtherailz/ny420kg9/ ) and maybe be more adaptive to fit various Iframe sizes (now it has only one layout for mobile - 1 column - and one for desktop - 6 columns, we should investigate to see what we can do to make it fit good in different sizes). Maybe the share tool could provide some options to fit it accordingly. It could be interesting