Because it's a bad release and not even worth using over Opus 5.5.

The improvement is marginal, it makes the same exact errors as Opus, but slower and much more expensive.

From what I saw, it has slightly better taste in some 3D mechanics, but mostly doesn't even bring discernible visual improvement.

So that people don't just reach out for it thinking it's the standard best model I guess. Opus is still, IMHO, the best intelligence per dollar, token, and speed.