Re: atemi at end of technique
I don't believe that it was mere coincidence that Funakoshi watered down karate by de-emphasising strikes to vital parts of the body, that Kano who once was enthusiastic about including atemi in judo, decided to abandon atemi except in a few kata and that atemi and vital pressure point manipulation were de-emphasised when aikido developed from Daito Ryu. These all seemed to occur around the middle of last century. The martial aspect of these arts had to be de-emphasised if they were to continue being practised.
In terms of the previously mentioned analogy of a finishing atemi with the nuclear bombs that were dropped - yes a good analogy: atemi can finish a conflict quickly and decisively and avoid the loss of life of the person/s being attacked by a foe who otherwise would not surrender easily.