If you want TOTALLY useless, as mentioned previously: Ice Axe Loops. I use ice axes. I've used ice axes for 35 years. I have NEVER used an ice axe loop to stow an axe, even temporarily. [Insert anecdote about clinging to a vertical wall by crampon points and on hammer while screwing in an ice piton with other hand - I have no such stories].
Actually, I've found that those are rather nice for holding collapsible trekking poles.
Alex