It's more about balancing the patient out, like with short leg syndrome (which sounds like a joke but is a real thing), to prevent back pain and related gait disorders. Having even a small variation in extremity length can really mess you up.
I love how even with this perfectly reasonable first comment on the page everyone is still using it as an opportunity to ridicule supposed vain people who go through this for non-medical reasons despite not actually existing.
I once watched a documentary about short men (is it on here somewhere? I don't remember) and they featured a sorta short guy who was paying for his son to get this done overseas. He was certain his son's life would be much better if he were taller than his dad. But this man had a nice house and a happy marriage to a pretty wife and 0k to waste on cosmetic surgery. What did he think he was missing that tall people were secretly getting out of life?