For many subscribers, it is just a matter of providing options. The EMF comes in like clipart, which needs to be ungrouped to be customized after you bring it onto your page. The downloadable PowerPoint pages need to be copied into your presentation and customized. Your choice.
For Mac users, the PowerPoint will be the only way to access the framework. We're always looking into more and different framework delivery formats. You may see additional options show up over time.