Question regarding crates

I am new to this sub and often read that many dog owners put their dogs in a crate while they are away or at night. What could be the reason for this? Not trying to start a debate, just want to understand. I've had dogs all my life, and pretty much everyone around me has dogs, but I've never heard of anyone putting their dog in a cage (except during transportation). I live in Europe, is it perhaps more common in the US? Thank you!