Dogs feel secure in small, enclosed spaces, like a den.
Dog crates make excellent dens.
It is a safe place for him to stay when you're away or when you cannot watch him. Watch your own dog around home. Yes, somewhere out of the traffic pattern where he has a roof overhead and a little privacy. A crate offers security, a den with a roof, and a place to call his very own where he can go to get away from it all. He should only have enough room to stand up, turn around and lie down.