Why did the attack Hiroshima / Nagasaki work so much better than 11 September?

(One event is a few months more recent than the cut of, but the other isn't, so hopefully it's ok)

I can think of a lot of reasons, so maybe the question could be "what is the biggest reason?"

Both were new / unusual and shocking / spectacular / terrifying attacks that killed large numbers of people and did a physical damage to the area in ways had not been seen before. Obviously Hiroshima / Nagasaki was much worse, but they're still similar in type.

Opinions on the effectiveness of killing hundreds of thousands of civilians in Japan range from "pointless" to "won the war", but nobody seems to seriously think it was counter productive to any plausible goal of motive?

Whereas the usually cited motive for September 11 is USA involvement in the Middle East, and it definitely made that worse.

It the goal was really "they hate us for our freedom" then the patriot act was a massive win?

So the goals of the nukes being clearer and better communicated was maybe part of it, but did the Japanese public have any idea what the goal was?