yeah it's mainly a benefit in summer.

In winter it can be beneficial if you also have a heat pump furnace. Otherwise the heat is ultimately coming from gas or resistive heating. That's not a problem, it's just not a gain in efficiency in winter. Actually it is slightly more efficient as he explains later in the video.

The main thing I don't like about my HPWH is it's a bit noisy when it's running.

edit: I have not had the random cold water issues he said he's had in the video. I wonder if that's more of a pressure problem in the hot water line. Assuming he doesn't take 120-degree showers, if the hot water pauses for a bit, seems like he'd temporarily get only water from the cold water line.