Well, I guess the second doesn't presuppose that it senses them. But I think you concentrated on the wrong thing:

Autopilot is not designed to steer around obstructions.

Autopilot is designed to brake for obstructions.

It sometimes fails to brake for obstructions. But it sometimes succeeds in braking for obstructions. It never steers around obstructions, even if it senses them perfectly.

Emergency braking is designed to lessen the impact, not prevent crash. See manual. This is mostly for avoiding crashes into a car that suddenly stops in front of you, I.e. in lower speed city traffic and jams. For this, detection within a few meters is all you need - ultrasound sensors might do. If the velocity delta is 120km/h, you’re not going to meaningfully slow down when already this close.