Why are swords sometimes given names?
Naming a weapon is seen in other applications than just swords. Some marines are fond of naming their rifles. It’s the concept that the weapon is an intimate part of what you are and what you do, keeping you alive and killing your enemies, defending your comrades and your country. When a weapon is what has saved your life you can develop a “relationship” with it and personification is a naturally occuring human trait. There are all kinds of benefits of psychologically personifying your weapon, you take better care of it, maintain it, prevent it from being damaged, and don’t misplace or lose it. If your life depends on the care and use of your weapon then giving it a name is a human response to that way of existing in a warrior culture.