My E90 is named, Betsy.
People name their cars just because. Some feel like a name will bring a closer connection and other are just that affectionate about their car. Same like when people call their girlfriend or boyfriend babe or have nicknames. Why do we do that? It's just a way of directing their love and to show affection. Haha. Random rant but yeah.
Also, how does your girlfriend categorize a person that names their car as a "no lifer?" I have friends who live a very social life and have successful careers that name their cars as well.