Maybe they expect drivers to treat it like beta software - "Please don't use these features in production cars. Make sure you keep backups of all drivers and passengers in case of bugs."
That spells 'not ready for production and release on public roads'.
Compare it to the regular cruise control, already present in production for years. Would you say cruise control is not ready for production or release on public roads? It's a tiny subset of what Tesla's update does. (and it doesn't even tell you when you need to take over)
If you're required to be ready to intervene that's about the worst possible way to introduce automated driving. And more to the point: the better the implementation the longer between 'interventions' the more likely that such an intervention will not be useful at all.