The thing with most traditional countermeasures is they're deployed upon detection of the threat, i.e. detection of a missile/torpedo launch. Hard to do that when it's coming at you at the speed of light. In addition, since it's a mobile gun, the line of sight is always changing.
As for previous giggling over the "Ponce", if it has frikken laser beams, what will the "USS Clint Eastwood" have for ordinance?? :O