I don't know much about this, but I saw a lot of prehistoric bone or stone harpoons point. Wood point, except bamboo, is weak and soft. and weaker and softer if wet. Y try spearfishing a lot of time, and I caught a fish just one time. With a metal point. I'm sure I won't be able to catch it with a wooden point spear... But perhaps I'm wrong.

And the fish I caught, I was in Morocco, on a sand beach. No risk for the blade.