When looking across the Pacific, a case can probably be made that the pre-invasion bombardments did little more than cause the marines to calmly board their landing craft thinking nothing could have survived the bombardment they just witnessed.
Iwo Jima was the first island that was part of Japan proper that we invaded. I think it was even considered part of the Tokyo prefecture, or whatever it is they call their counties.
The carnage we experienced there goes a long way to explaining why so many Americans dreaded the coming invasion of Japan. And why so many were so relieved when we nuked ‘em.