Good points.
I have read that President Truman was interested in using the A-bomb for this very reason, that it was hoped it would bring a quick end to the war.
The war could have dragged on for years if we didn’t use the bomb. A conventional invasion of Japan would have resulted in many more casualties, on both sides, than the number who died at Hiroshima and Nagasaki.
Liberal revisionist historians condemn the atomic bomb, but tend not to condemn the firebombing of Tokyo, or the bombing of Dresden as harshly. It’s as if liberals are ok with people dying with conventional weapons, but somehow, using an atomic bomb was not proper.