That was my point precisely, which you got. My thinking was that cluster bombs, or bomblets were the ultimate anti-personnel weapons. They do not have sufficient explosive power to put holes in runways. They will decimate airplanes with thin structures, but are not effective against armored vehicles. In vietnam we did have some airplanes that carried WWII bombs that contained numerous fire producing clusters of the kind used against Japanese cities, and were great at area bombing at night, when the aim was not near as good as day time.
Comments based purely on memory, and not recent research.
MK-20 Rockeye
The MK-20 Rockeye is a free-fall, unguided cluster weapon designed to kill tanks and armored vehicles.
The system consists of a clamshell dispenser, a mechanical MK-339 timed fuze, and 247 dual-purpose armor-piercing shaped-charge bomblets.
The bomblet weighs 1.32 pounds and has a 0.4-pound shaped-charge warhead of high explosives, which produces up to 250,000 psi at the point of impact, allowing penetration of approximately 7.5 inches of armor.
Rockeye is most efficiently used against area targets requiring penetration to kill.
Fielded in 1968, the Rockeye dispenser is also used in the Gator air-delivered mine system.
During Desert Storm US Marines used the weapon extensively, dropping 15,828 of the 27,987 total Rockeyes against armor, artillery, and antipersonnel targets.
The remainder were dropped by Air Force (5,345) and Navy (6,814) aircraft.
If it will penetrate 7.5 inches of armor, I garontee it will put a hole in a concrete runway.