Furthermore, your beloved T 12 will be useless in Vietnam. Blanketing an area with many, smaller munitions has much greater utility against widely spaced soft, surface targets than one bloody enormous 'bang'.
Except the first Daisycutters for clearing LZs were old T-10 aka US made Tallboys
Sometimes bigger was needed.
Like the Dragon's Jaw Bridge, that 500 pounders bounced off from.