When uploading a PNG Sequence initially it didn't play at all, which seemed to be due to the images being too many images or memory being taken up (2000x2000). However, when I halved the size, now it plays but at an incredibly low frame rate. The video about animation support showed a Frame Interval setting—but this current version doesn't seem to have any such thing now... (´ｰ ｰ`;)
That said, even making the PNGs even smaller, there doesn't seem to be any clear cause for the animation not working. I don't know if it would help—but Animated-PNG or even GIF compatibility would at the very least make what to expect from the consistency clearer.