Sure I do:
1. For snorkeling or my pathetic attempts at free diving.
2. As a prop to keep the door open when I'm moving gear.
3. When assisting at open water classes, where it is required, if for no other reason than to demonstrate its utter and complete lack of utility.
4. To dig in the sand while looking for artifacts.
Seriously, I don't find it useful for the dives I do. Even when shore diving, I float on my back, so I don't need it.
In addition, it interferes with the deployment of my primary hose (which is a 7' hose routed across my chest and around the back of my neck) during out of air drills.
Finally, it is a potential source of entanglement in overhead environments.
Welcome to the Board