OTOH, the K't'ingas without torpedoes in DS9 "Way of the Warrior" could have been specifically modified for bombardment of space stations and planets. They were older vessels, after all, perhaps no longer fit for ship-to-ship combat duty.
If Gowron's military campaign was to involve lots of bombardment, the red-beam weapon might have been superior for that, there being no demand for extreme range or any degree of maneuverability. And a large old battle cruiser would be an excellent platform for mounting this weaponry.
When the beam is seen again in "Rules of Engagement", it is in a low-intensity scenario - a turkey shoot at a transport convoy. Even a suboptimal, bombardment-modified vessel could be sent to do that. Especially if the Klingon plan involved sacrificing the vessel in order to make a political point. Who knows if the old cruiser even had a crew on board...?
Timo Saloniemi