that was more of a power grab on capone's end. the old man didn't want to get into prohibition. that's what capone was telling jimmy when they were outside at the car. torrio (butchie from the sopranos), had him killed, and capone delivering the shipment showed that it was the beginning of their new venture. i don't know how true to life the show plans to be, but torrio actually did have colosimo killed in real life

on jimmy's end, he was able to prove to nucky his value. plus he was able to use the feds to get back at the guy he was fighting with, by tipping them off on the location of the still

it was just good timing that nucky and his brother were able to set up the husband, as the robber, that way rothstein and luciano won't find out who really took their shit.