Timers, lights (it's a high tech Clapper, lol), and controlling the video stream to my TV (next episode, fast forward, etc.) are the three things I use most often with Assistant. I've got a Google Home for it, so no pulling out my phone and hands free (great when I'm using timers for cooking).

I also use Assistant's call screening, but I don't think there's any AI involved with that, just playing a recorded message to the caller and voice-to-text for their response (unless they hang up, which they usually do).