I wouldn’t exactly compare this to stage manager.
Stage Manager basically had no steaks, it’s hidden away in control center, it’s clearly a power user feature. If It failed the worst thing that happens is you don’t use it.
Meanwhile, this contextually aware Siri literally has access to, can read, modify and delete all the files, photos, messages, emails, etc on your device.
Not only are there major security and privacy concerns with this type of technology, but also just very basic reliability concerns.
If you say “delete this file” and in response Siri deletes the wrong file or worse, starts deleting multiple files, you’re going to have some major problems.
60% accurate isn’t even close to acceptable for even a public beta test for something that’s dealing with such a high amount of sensitive, very personal data.