In the past two days alone, I've gotten over 20 spam calls with none of them leaving a message. Just 3/4 seconds of silence on my voice mail. One call the other day left a 22 second blank message.
It answers the call behind the scenes without you needing to hear or listen. It pops up a notification saying that the call is ongoing with the screening AI, and you have an option to immediately stop the call or to pick it up. It also records a transcript of the call for you to listen to afterwards. It also doesn't screen every call, if it's a number in your contacts it lets it through to you as normal.