> the animation adds no additional information.

No it removes information; to be able to focus on one period at a time as it evolves.

Seeing a "living graph" of how something evolves is different than seeing the graph fully drawn statically, that cannot be considered chart junk IMO.

Following the parent comment's idea, it'd end up in a table being the best choice 100% of the time.

Because the underlying assumption is that accessibility and the ability to grasp the data that is being conveyed isn't completely dependent on the audience. If I happen to prefer a static chart, an animated chart might still convey the intended thing in a stickier way, to a wider audience.