It's not self-contained, it requires PowerPoint to be indfled. Which is not an issue on corporate machines of course, but maybe you want to do a presentation for a general/broader audience.
That's besides the point though. With a self-contained HTML, you don't need to go to a special website, you don't need an account or sign-in, heck you don't even need the Internet, and it works pretty much on every device that supports HTML5.
