I know they picked civilians-only cities to drop the bombs cuz [white noise screeches], and their priority was for Japan to surrender to the US instead of to the URSS, which coincided with what Imperial Japan wanted.
And I also know the nuclear bombings weren't immediately reported as anomaly cuz conventional bombing campaigns caused similar immediate results
That said,
I always wondered if they could have dropped the bomb in the sea in front of Tokio so the capital would see the fungus, feel the heat blast and the mild tsunami but without civilian casualties; and so scare them into immediate surrender without doing a massive war crime