Hard to argue that having this functionality in the type itself is better than having to do so in images. It has big advantages over SVGs, as well. I can copy styled text, for example.

So it's not like this would empower people to do ugly web design that they couldn't already do.

Per your point, I prefer CSS animations to having a blink tag, and people have managed to avoid using those too much the last 20 years.

AFAIK it was Apple that first added color to fonts in a modern OS. The fonts render in Safari and Firefox. Google is just publishing some fonts.