By most approximations, there were about 200,000 causalities from the bombs and their aftermath.

That said, had the bombs not been dropped, estimates ran into the millions for Allied casualties and tens of millions for Japanese (civilian + soldiers) casualties.

Ultimately it boils down to an issue of numbers (achieved by expediency).

Definitely. In general, though -all other things being equal- if I have to decide who dies, I will decide they won't be people fighting on my side.