This is an unfortunate trend I continue to see: Where a company with a positive reputation, say Google, is given the most altruistic read on what their decision is for, and a company with a negative reputation, like Comcast, is assumed to be evil.
Many people's issues are, in fact, solved by the Comcast automated system. Generally if you call in to report an outage, and it knows that there's an outage associated with your area already based on the phone number you call from, it'll drop you out of the tech support queue, let you know that the outage is there, and what time it is expected to be resolved. This is the most common reason I call Comcast, and most of the time, it's an outage they already knew about, so this saves me time. (Of course, the times the line just to my building was severed, getting to an actual human to explain my problem is much, much harder.)
Similarly, all of the automated features to trigger remote resets of your modem have been implemented specifically so that if you have a simple problem (as most people do), you can get it quickly and automatically resolved without having to wait for an available human. I know how to reset my own dang modem, so this just adds another burdensome and annoying step for me... but for the average user, it's probably wildly successful at concluding calls. I assume.
But sometimes, when you or I call, we probably have more specific or detailed needs, and find this entire process absolutely horrific to suffer through. But surely, just like the Googlers who thought Duplex was a good idea, someone at Comcast realized it would drastically reduce call volume and speed response time if an automated system could do simple tasks automatically.
Similarly, Duplex will probably do it's job: It'll make it easier for people who don't want to be bothered to make a phone call to schedule an appointment. It'll reduce their call volume. But the humans who have to interface with it will likely find it exasperating.