Regarding dogs: Why aren’t waist leashes/belts more popular?

Been using one for years from Alpine Outfitters.

You’re hands free with control. You don’t have to keep a hand on the leash, but you can feel the dog in when necessary, the dog has more freedom of movement but is still restrained, if there’s any sort of pulling it’s tied to your center of gravity, etc etc etc.

To me it seems like the best way to hike with a dog.