Also, I calibrate all of my home's TVs with a calibration disk and meter. One of the requirements to accurately calibrate your TV, is for it to be on the warmest setting (like Warm 1, Warm 2 for example). This is because it causes the white point of the TV to be a natural TRUE white and not an LED cold looking white. This is what directors, illustrators, etc go by and what they want the end thing to look like on our end. The interesting thing, is that you have to calibrate it in the lighting that you're going to usually be watching the TV in. Because that drastically changes the picture quality; like contrasts, white balance, colors, brightness, etc.
True Tone basically keeps the white point and colors as accurate as it can to the calibration specifications in all environments. I think it can still be improved and hopefully Apple does True Tone 2.
A calibrated monitor or screen isn't really a "preference" because the intended image or video is meant to look a certain way but the director or creator. This is where people are "wrong" and say a cold screen looks better. It doesn't lol and it makes everything else look incorrect.
As a person who calibrates his own stuff as a hobby, I was quite shocked Apple came up with it and made it go mainstream. Pretty cool stuff IMO