Our dogs, even though only two are regularly crated, are all crate-trained. It has come in very handy when we have taken them on vactions and had to stay in hotels or at family member's homes.
Our Paula loves the crate; that is her nap spot of choice when we are home (with the door open).
Boo is spastic and gets spooked easily, so we feel that crating her when we are gone from home is the safest option. I fear that she would hurt herself by trying to climb out of windows, chew through furniture, or get into cupboards. When she is older and more sedate, we do plan to leave her out. For now, she relaxes and enjoys sound, undisturbed naps in her crate.
Pup is a puppy, and I worry about her getting into things just like Boo. But she also sometimes gets on the nerves of the other dogs, and they could injure her intentionally or accidently. She is in a greyhound-size crate, and has plenty or room to walk around, pplay with toys, etc.

For us, crating works. I feel that all my dogs are in a safe environment when we can't be there to watch them.