I'm not about to hop on the "I hate Flash" bandwagon just yet though. Because...
Then again, the same could be said about webm files. In fact, flash support is even wider in comparison, considering that you have to install the webm codec separately to make it run on anything Apple-branded (regardless of whether or not you're using Firefox or Chrome), or anything Microsoft branded (IE), so good luck if you're working for IT and don't have other options.
The show itself is still Flash based, almost entirely from start to finish. And it probably will be that way until the series is over. Why? Well, if you're involved in a project where all of your assets are confidential and not web-based in the first place, what real reason would you have to care?
Thirdly, despite what people may think of Flash, looking at it from the outside in, the reality of it all is the fact that not just a majority, but literally almost every last fan animator out there
still uses it. You can find plenty of flash projects in the fandom. Many thousands of them. I've only ever seen one, or maybe two html5-based animation projects out there though of any sufficient level of completion.
C'est la vie. We're not ready for alternatives just yet.