In his great novel East of Eden John Steinbeck said that having a nickname meant that somehow your own name didn’t quite fit you. I’m not sure I would agree with this.
In my experience people and families that enjoy creating and using nicknames generally have a love of language. They like to play around with family memories and words. I think anything that cultivates pleasure in using words and language creatively and having fun with them is a good thing.
My daughters enjoy being Princess Duckface and The Mechanical Monkey because of the good memories that led to those nicknames. There’s also something generous in awarding others affectionate nicknames — it shows we think about them and care for them.