Yes, but the T2 has much more control over the boot process and hardware. The T1 was relatively isolated, communicating with the rest of the computer only for Touch Bar related stuff, and verifying data in the Secure Enclave.
Not entirely true. The T1 also controls the FaceTime camera, TouchID and probably parts of SMC functionality (ambient light sensor), although that last one still has to be confirmed.
TouchID is part of the Secure Enclave along with Apple Pay and the keychain. I’d expect the FaceTime camera is wired up to it for security, to prevent access from malicious programs. Is the ambient light sensor used for controlling the brightness of the Touch Bar?
I'm pretty sure the FaceTime camera is wired up to the T1 chip so apple can avoid an extra 3rd party part that connects the camera to the system via USB.
Those 3rd party USB webcam chips are also notoriously bad for image quality. This way apple has total control over the image processing of the camera, using the same technology/software they use on the iPhone.
When using macOS the ambient light sensor is afaik only used for the brightness of the keyboard backlight.
The brightness of the TouchBar isn't related to ambient light and just depends on the usage of the MacBook Pro. In use it's simply on with full brightness, after 1 minute of inactivity it dims to a certain level, before shutting off the TouchBar completely 15 seconds later. While macOS doesn't allow to customize these timeouts, the experimental Linux driver [1] does.
