So most (if not all) Devil Fruit powers are connected to their user’s Character/Personality. Luffy = Flexibility or the freedom to do whatever he wants, Law = Doctor, Katakuri = mochi is shaped and molded as desired just as how he was shaped into the role by the pressure from his family, Doflamingo = Puppet Master, etc…
With Nico Robin it took me a while to figure out what the deal was with her Devil Fruit since Oda puts a lot of thought when it comes to designing characters. I started wondering what the deal was with all the hands, legs, and limbs that Robin was producing.
Then it hit me, this woman was literally on the run for 20 years and couldn’t depend on anyone but herself. She literally had to be the one to give herself a hand to pick herself up or a leg to stand on throughout her life till she met Luffy.