Steve Callahan actually used a speargun not a spear there is a major difference tho Im sure a spear woulda worked well in that situation too.
It's a good idea too, but once getting wet, even hard wood quickly get softer. And a soft point can't pierce the scales of a medium sized fish. But yes, it would serve.
You can always figure out ways to incorporate the wire to the stick to make a better spear would loveto see what you come up with.