A very fascinating article,
"The Bomb Didn't Beat Japan, Stalin did", paints a compelling view of the irrelevance of the use of the atomic bomb in Japan's surrender.
Presuming it is true, then maybe the atomic bomb was not so much for Japan, but for a message to other global powers, in particular, the Soviet Union.
The article is well written and lays out some compelling arguments, but doesn't really address why The Bomb was used. It tends to be myopic on that issue and doesn't account for other world dynamics in play. However, it is fair to point out the article is focused on the relevance of the bomb to the Japanese surrender and not an explanation of why such a device was used at all.