Why navies trusted torpedo bombers

Why did naval aviation emphasize torpedo bombers into the Second World War?

Navies favoured proven weapons when spending their money. Torpedo aircraft already had a wartime sinking to demonstrate that they could destroy ships.

Naval procurement favoured weapons with demonstrated results. Aircraft had already sunk an Ottoman merchant vessel with a torpedo, giving the torpedo bomber a wartime record. That example had limits because the merchant vessel had poor damage control. Later bombing demonstrations therefore faced a more specific problem than simply proving that aircraft could sink a ship.