I am not a guru but I do tend to overbuild just like most of the other custom guys.
Your right about the bond with regular glue is stronger than the wood fibers but the expanding glues also penetrate into the wood fibers a little more. This further reinforces the integrity of the bait without adding much weight to the bait. Think of it as a backbone for the bait, between the wire and the glue the bait is much stronger.
Also the polyurethane glues cure faster than most of the yellow wood glues which is another positive for me.