So, for the telephone system, metadata is not what you say on the call. It is whom you are calling, who called you, and the relationship between the callers. It can even be where you called from.
Metadata is a very useful law enforcement tool. If they think that a person is a suspect and they know that someone else was definitely involved in the crime, if those two people call each other, that is an important tool for the police.
Again, we would only provide metadata with a warrant or an order. We would never provide metadata without a warrant or order.