I think the difference the OP mentioned is that Ractive templates are mustache-formatted strings, and can be stored in external files. So you have a JS file and a template file, not the combination of both you find in React.
Yes, indeed. I actually tried for a bit to get React templates in their own files separate from the JS, and I just couldn't do it. I know the React team's reasoning for why it's this way, but I still think it should be something devs can do if they want.