Here's an interesting piece of info I learned some years ago:

Do you know when the last time was that the US military purchased purple hearts?

Late 1944/early 1945. They've never had to purchase more, not through Korea, or Vietnam, or the various other conflicts the US has been involved with since then.

Why? Because they expected to need an extremely large number of them in the invasion of Japan.

I often find that people who rail against nuking Hiroshima and Nagasaki don't understand the historical context in which the decision to bomb the cities was made. Having only known a world where the US is a superpower they don't see that when you're locked in combat with someone you see as a peer -- and who fights under a code of ethics that sees surrender as both dishonorable and evil -- you use all of your might.

You also do that because World War I taught you an important lesson: you can't risk "just" forcing your opponent to lay down his arms. Not when your opponent is a modern, industrialized state. You seek unconditional surrender because anything less than that means you'll probably have to fight another war against the same opponent within a generation.

Getting Imperial Japan to accept unconditional surrender required making it clear that the price of not capitulating was utter ruin. As it was, it took over a week for the Japanese high command to make the decision, and they only agreed after the Emperor was guaranteed protection and immunity.