I've only seen that on plastic handles.
I've talked to blacksmiths and carpenters.
Old guys and young guys that have done it for a while, they have all recommended a hickory handle.
When it is properly fitted and wedged, I have never seen a handle come loose.
Often they also recommend dropping the whole hammer head first into a can of thinned boiled linseed oil for a day or two.
It protects the handle with the oil finish, keeps the fibres pliable and flexible to absorb shock and reduce breakage, and helps to keep the head tight.
Framers that used solid Estwing hammers mentioned that that shock would go all the way back to their shoulders until the old ones told the new ones to go Hickory..