I can, but I usually don't want to :) I'd rather not force everyone who happens to open the page to download 20 MB before they decide to interact with the code.

The network may be fast and the traffic cheap in some parts of the world, but not in others.

Bad idea, not ever one has an unlimited data plan.

There may be some middle ground where the download starts when you click in a text editor, or hover over the "run" button