Scrivener isn't a word processor or editor as much as it is a project management tool for writing. The point is that you just focus on your writing as you use the tool and then compile it to whatever format you want, including plain text and MultiMarkdown. While Scrivener does support some level of formatting in the editor, that's mostly for convenience as you work with it, as far as I can tell. The final format of the output of the project occurs when you compile it.
Even having the possibility of all the crap that goes along with copy-pasting and broken formatting is a negative for me, not to mention the wasted hotkeys.
I hope that helps.