Knowing that your dog is comfortable in a kennel should bring you peace of mind.
Kennels keep your dog from being underfoot, especially if you have safety concerns. Whether it's a service person working at your home, or moving day, or any other activity where your door could be opened and closed repeatedly, if your dog is in a kennel or crate, then you know where your dog is. The dog won't escape from a closed room either.
Kennels can provide a structured, but relaxed environment for your dog after a training session. Placing your dog in their kennel after a good mental workout gives them time and space to let the trick, cue, or lesson sink in.
Having your dog properly trained for a kennel or crate also makes you better prepared for an emergency evacuation. If you had to fly out of your city, airlines will require dogs flying in cargo to be crated. I want my dogs to feel secure when they're in their kennels.
Once your dog feels safe and comfy in his kennel or crate, finding time to practice this skill is easy. How long your dog should be crated varies by dog and circumstance.
If you anticipate tasks around the house where you could let your dog relax in their crate while you work, then that's some easy training time. Since I don't want to forget about the dogs in their crates, I usually set a timer.