I started showing Bullet in obedience competition and discovered that standing around all morning waiting to go in the ring was a bit tiresome for both of us. People and dogs would walk nearby and I had to be vigilant about keeping him from engaging with them. If I wanted to watch other competition or visit the vendors he'd be forced to tag along with me. I started bringing the crate to reduce the fatigue on both of us. When it was his time to compete he would emerge from the crate refreshed and eager to participate in the ring.
The crate never saw the inside of my home for several years until I set one up in the living room for a foster dog. I slid it into a corner and, before I stepped away, Bullet was already snuggled down for a nap. He continued to choose the crate over the plush beds that I had placed near it.
As more dogs passed through my home I realized what a valuable tool the crate was in daily dog management. When Bullet needed hip surgery he was cooperative with the vet staff as they hauled him in and out of a small kennel during his hospital stay. If needed, I could crate the dogs up instead of sequestering them to a distant room when service people came into my home. If I accidentally broke a glass on the floor or dropped food, I could send them to their crates to keep them out of the way during clean up. Maids could come into hotel rooms if I wasn't present, shy guest dogs could come into my house without being bombarded by gregarious dogs, and multiple dogs could have chew bones with no stealing or guarding behavior.
I have used crates to stop excessive barking, teach overstimulated dogs to settle, and help with separation stress.
I understand when some of my clients say they will never put their dog in a cage. I felt that way myself at one time. Caging a family member seems, at the very least, a bit awkward. However, most dogs, properly introduced to a crate, really enjoy them. Sure there are a few dogs who have had bad experiences and may never do well in a crate but, for the most part, it is a great tool in dog management.