Yet people don't understand display calibration at all. If you put two displays from two different manufacturers side by side they may not have the same calibration because display calibration also depends on lighting conditions where you are viewing it which means factory calibration may not be perfect. True Tone is meant to correct this since you are not going to use your phone in a single place like you would a desktop display.
On top of that humans have very unreliable color vision. It can be fooled by having a different color object right next to it as well as lighting plus individuals perceive colors in different ways. I can look at my previous phone and on its own it looks perfectly fine to me but put next to my iPhone I can see it has a blue tint. We are also quick to adapt, for example I felt the most accurate default color setting on my Samsung TV looked too warm initially (coming from a more blue-tinted setting) but now it looks just right.
Of course there are also real problems like display uniformity but people are quick to say that their phone does not look right when it looks different from what they are used to, even if it might be a more accurate calibration.
