Massive scale strategic bombing and nuclear weapons are not substitutable from a military strategy standpoint and everyone would have understood the implications of that. Any similarity is superficial.
The massive bombing of Japan was a grinding war of attrition that has well-understood limitations and challenges. Military leaders in Japan were perfectly capable of understanding what those campaigns couldn't do, so it came down to a willingness to accept the losses to maintain strategic optionality, which they clearly were.
Most of the limitations of strategic bombing campaigns do not apply to nuclear weapons, which is something the Japanese military leadership also understood, though the scope of capability was uncertain (which also probably helped). If the US switched to nuclear weapons instead of conventional bombing campaigns, which was the risk Japanese military leaders had to consider, it takes most of the strategic optionality off the table at which point there is little to gain by continuing.
The massive bombing of Japan was a grinding war of attrition that has well-understood limitations and challenges. Military leaders in Japan were perfectly capable of understanding what those campaigns couldn't do, so it came down to a willingness to accept the losses to maintain strategic optionality, which they clearly were.
Most of the limitations of strategic bombing campaigns do not apply to nuclear weapons, which is something the Japanese military leadership also understood, though the scope of capability was uncertain (which also probably helped). If the US switched to nuclear weapons instead of conventional bombing campaigns, which was the risk Japanese military leaders had to consider, it takes most of the strategic optionality off the table at which point there is little to gain by continuing.