There have been stories in the media about people receiving treatments on the NHS that are purely cosmetic. A doctor had to give the go-ahead, though, and there may be good reasons why it was done. Psychological reasons may be valid, and if it means that the person can function better in society, then it is good.
I would be very cautious about banning a treatment or procedure to be done on the NHS. People are receiving maybe inappropriate treatments all the time. For example, getting antibiotics for a viral infection, getting admitted into hospital for a social problem, getting a 'sick note' from the doctor when you are not really ill.
Those things mentioned are genuinely needed in other cases.