This has a lot of potentially cool applications in browser game design, particularly for handling intensive but deferrable tasks like AI calculations, by splitting them into manageable chunks and letting a director determine which tasks are highest priority.

It'll probably be a while before this API spreads to other browsers, but if you can live with only developing for Chrome (or you're prepared to put in the extra work to support a standard task scheduling pattern alongside this one), this could be a really interesting feature for improving performance.