Pyrethrin and its derivatives offer a fast knockdown of whatever insects are in its vicinity, but does not offer anything in the way of residual killing like many organophosphates will. In other words, once it's gone, it's gone, and it goes pretty quick.
It is often used for indoor fogging because of this characteristic. I have not heard of it being used in outdoor fogging applications, and do not believe it would be particularly effective because in-migration to the fogged area would be able to begin almost immediately.