...well both bombs AND missiles can be equipped with kinetic (inert) rounds. Actually, the Navy tested this idea several years ago (by equipping Trident missiles with conventional warheads---and I'm sure they tossed the idea around of using inert rounds instead of conventional ones).
There is always a risk of ejecting fissile material from the impact site.
It's certainly one of my personal concerns.....given the toxicity of the by-products can--and will--contaminate underground water sources, local farms/ranches, etc....