Growth excellence is good for career advancement as well as for communicating with your surrounding Sims. For example, the more charming a sim is, the easier it will be for him to make friends with others, successfully joke and flirt, he will be able to conduct longer conversations, improving relationships, even despite his growing up.
It is especially useful to develop a charm for sim-romantics and those whose life purpose is popularity. It will be convenient for them to work in a profession in which this skill is in demand. You can develop the level of maturity codes in front of the mirror or use professional rewards by training at the “I Protest” lawyer platform (award for work in justice, available in the Seasons add-on), on the teleprompter “Joy of Bush” (political reward) or playing mini-golf (Business). But for this, the sim will have to grow up.