Where are you getting that from?

Here. I'll show you mine:

https://www.tesla.com/model3/design#overview

Scroll down to the feature add-ons.

Full Self-Driving Capability

$12,000

Your car will be able to drive itself almost anywhere with minimal driver intervention and will continuously improve

All functionality of Basic Autopilot and Enhanced Autopilot

Autosteer on city streets

Traffic Light and Stop Sign Control

The currently enabled features require active driver supervision and do not make the vehicle autonomous. The activation and use of these features are dependent on achieving reliability far in excess of human drivers as demonstrated by billions of miles of experience, as well as regulatory approval, which may take longer in some jurisdictions. As these self-driving features evolve, your car will be continuously upgraded through over-the-air software updates.

Maybe I'm a bit out-there but the bolded section seems to indicate to me that this is something I need to pay attention to the road while using, and am told this before I add the feature to the car before checkout.