What is the lasting effect of nuclear weapons? Residual radiation and fallout will hardly affect the land if the warhead is detonated high in the air like in N

What is the lasting effect of nuclear weapons? Residual radiation and fallout will hardly affect the land if the warhead is detonated high in the air like in Nagasaki and Hiroshima. The fallout relative to the explosion radius is also smaller with a thermonuclear weapon. The number of people that die from higher cancer risk due to radiation is actually lower with a typical thermonuclear weapon because the lethal blast radius is bigger. So I don't think the lasting effect on the population is a good argument against nuclear or at least thermonuclear weapons. My view is that nuclear weapons are really dangerous because you don't need a lot of resources to deploy them and the high density of destructive power. It is much easier to "lose" 1MT worth of TNT with a nuclear warhead than with conventional bombs. It is also easier to deploy that 1MT worth of TNT if it is just one bomb. A mistake with a nuclear weapon can also cause a nuclear war. Now it isn't a single nuclear warhead against 100k conventional bombs, it is thousand nuclear weapons against maybe a few million conventional bombs.