If anything has become apparent in the last few days on social media, it is that Americans suck at math.
Just a friendly reminder, Little Boy, the enriched uranium bomb dropped on Hiroshima, was 15 Kilotons equivalent. The “kilo” in Kilotons is very, very important.
The GBU-43/B, which is full of Composition H6, which has a 1.35 RE (or relative effectiveness to TNT), is accurately about 11 tons equivalent.
Which is greater, 15,000 or 11? Pretty obvious when I put is plainly like that.
Now, realize that Little Boy was essentially a trial run, a working prototype, and was one of the least efficient atomic bombs ever created with a less than 2% fission efficiency. To drop enough MOABs to equal the energy of Little Boy, you would have to drop 1,363 of them, and at 16 million per ten MOABs that’s a 2.182 Billion dollars not including any costs associated with 1,363 mission sorties (honestly the cost per system is going to vary quite a bit, depending on lot size order and other factors, I’ve seen it as low as 160,000 per unit).
Did we absolutely need to use a MOAB? No. But was it the right choice to use against a large, unknown layout, well defended cave complex? Most likely.
If you dropped a MOAB into a major city, it would likely rubble a few buildings and knock out a whole bunch of windows, the death count would be high, but probably along the lines of something between Oklahoma City and 9/11. Dropping something like Little Boy on a city is still the stuff of nightmares, and the death toll would be estimated only because complete traces of people would be erased from the face of the earth.