Besides the points made by the sibling comment, this feature is crucially important to JavaScript. It hasn't been implemented yet because the spec itself is jus

Besides the points made by the sibling comment, this feature is crucially important to JavaScript. It hasn't been implemented yet because the spec itself is just now being finalized. This page was made in an effort to spread the word about the upcoming modules, which people really need to see now and understand because it's going to be a big change. I don't see how it still can't be crucially important.