Here are some reasons why: Prevents it from rotting and splitting. It helps in combining the ingredients uniformly while cooking some food that has more liquid content.
Gluing wood trim to tile
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Small round wooden tray
Wooden Spoon with Hole in Handle eBay
The hole in the middle of a wooden spoon helps prevent it from rotting and splitting because the end grain of the wood (its growth rings) is more vulnerable to moisture than its side grain, so having the hole in the middle allows any moisture to drain out.