I think the atomic bombs probably saved more Japanese than American lives.
A conventional invasion of Japan where every Japanese down to the small children were indoctrinated into the idea that they must kill or die was going to be a horror.
A tour of Shuri Castle gives you an idea of how hard the war was going to become. It was leveled. In the Battle of Okinawa they were forcing Okinawan boys of fourteen onto the front lines.
How can you ask your men to shoot children?
How can you live with the casualties if you don't?