What if a targets in a high population area though? Drop a gamma bomb in and you can march your troops in later and pick him up, no fuss no muss. Given all the crap we get for blowing up terrorists who hide next to schools, hospitals or other targets that provide great proproganda tools when blown up, how would the army not love a weapon that creates no PR disasters?
As for Rick Jones, bear in mind this was an early stage bomb. Bruce thought it might only destroy buildings, and had no idea that it would actually turn someone into a reflection of their subconscious self image. He had a ways to go with regards to research ;)