Limit the reach of your selectors with the CSS scope at-rule (developer.chrome.com)

I may have missed it, but what is the difference between `@scope (.card) { img {} }` and `.card img {}`? From an implementation perspective, I can see that scope might be calculated beforehand, so only that tree is searched for `img` elements (which would be faster than the default right-to-left way it's normally don), but is that the only real difference between these two selectors?