Cut-resistant gloves help protect the wearers hand from cuts when working with or around sharp knives. The level of cut resistance can vary based on the materials, methods of manufacture, and intended level of protection.
They would be a recommended addition to your leather working tool kit, where both or one can be work, whenever appropriate. For example, if the right hand is holding a cutting knife and the left holding the leather, maybe wear a cut resistant glove on the left hand as that will be nearer the cutting blade.
Leather crafters have gone for centuries without them, and they’re not an absolute need. Though it’s always helpful to be protected if reasonable and in some cases these can help.