Hairstylists come in two varieties: technicians and artists.

A technician can perform the basic functions, give you a haircut, perm, maybe some color, style your do for you and make you look nice that day.

The other flavor of hairstylists, the artist, can transform not only the way your hair looks that day, but how it grows, its health, and how it affects the rest of you. A superb haircut, color change, etc. can do a lot to, not necessarily stroke your ego but, remind you to take care of yourself. Part of that is managing the way you look.

Needless to say, the artist version of hairstylist must be a professional, one who is constantly learning. There is much science in altering hair color, and you must possess a certain degree of intelligence and critical thinking skills to assimilate and apply that science.
There is much art in creating a good cut with a person's head of hair so that it grows with the cut, not out of it.