It has been available, since yesterday, within Google Flow. I know, because I used it yesterday. Creatives normally are using Flow or similar third party tools, not APIs or AI Studio. The claim here is that there is more character consistency, which is helpful if true. But that's not something I can see from a little work. Despite the "More Affordable" claim, it costs more, and the outputs doesn't, from my limited experience so far, seem to be significantly better. So I could only, personally, justify pulling this up when character consistency is punching me in the face. Which, to be fair, is a lot of the time, both in my experience, and the experience of other AI film makers I talk to.
This isn't for (most) coders, it hardly matters if it shows up on Flow a little earlier that Google Vids, and, perhaps, it is a little silly to act like it is a nightmare that a rollout occurs over a few days, especially the rollout prioritizes the paying creatives on the tool that are most likely to use.