The only reason I had heard of it was because my car has it built into the navigation system. So, I can enter a W3W coordinate and my car will appropriately route me.

It's supposedly beneficial when trying to locate a particular person. They can just send you their W3W, the car can read it off the SMS, and automatically provide routing.

I have not used the capability, but explored it when I first got the car since I had never heard of W3W.