I used to when I lived in San Diego. Great fun. I used a Hawaiian sling, not what most consider spearfishing. It sure is a cheap tool to get the job done.
I watched a friend spear a trigger fish off northern FL. Down there, they place stringers through the eyes. The fish flipped around and bit my buddy hard in the thigh. The fish died, but definitely had the last laugh.
I tried it in Hawaii with snorkeling gear and a sling in less than 20' of water. What a challenge it was! I have the utmost respect for the locals who free dive in 50'+ and hunt BIG fish. The currents were no joke between Molokai and Maui.