There are so many reasons to crate train your pets (and I'll focus on dogs here) that I don't even know where to start but one that rarely gets discussed is the issue of disaster preparation.
In the event of an emergency, especially an evacuation, it is almost impossible to flee with dogs who are not crate trained. If you have to go to an evacuation center, they will not take dogs who are not in crates. And if your dog is not used to being in a crate he's going to freak out. He'll bark incessantly and possibly hurt himself trying to get out. He may get expelled from the building for this behavior, which may land him being crated outside where it is less comfortable and less safe.
People may think they can flee with their dogs in their car, loose. But what happens if the dogs have to stay in the car for hours at a time, and it gets really hot during the day? If your dog is crated inside your car, you can open all the doors and windows and create enough airflow and cross ventilation to keep your dog cool yet safe at the same time.
If you work at a hospital or facility that becomes "mission critical" in the event of a disaster, you will be needed at work for days at a time. If you don't have someone reliable to step in and care for your dogs you may need to be able to bring them with you and keep them with you for days at a time. Again, this will be almost impossible to safely manage if your dogs are not crate trained.
If they are crate trained, they can be safely contained almost anywhere. You can evacuate to a hotel that doesn't take pets because your dogs can be safely kept in the car. Because they're crated, the chances are higher that you'll be allowed to keep them in the room.
Crate training should be a life-long practice, not just a puppy potty training tool. What I mean is that your dog should be cool just chilling and hanging out in his crate when you ask him to. So to keep that behavior "fluent", you need to do it often enough that it's not a big deal to the dog, it's not horribly unusual. This doesn't mean you're crating for too many hours, etc etc-- I'm not talking about something abusive. But we need to be able to safely park our dogs for awhile, at our discretion, and it's our job to make that experience pleasant for them, not strange and frightening.