Because...? As far as I can tell, they offer no significant technical advantages over Git. And it doesn't make sense to leave Git just for the sake of diversity

Because...? As far as I can tell, they offer no significant technical advantages over Git. And it doesn't make sense to leave Git just for the sake of diversity, as it's just a tool, and the fact that most developer know its basics is very useful - you don't lose much time dealing with version control training for each new project.