It's an old robot from a time when giant mecha neurotronics were rough and the nuclear dropkick maneuver wasn't yet fully developed. They were equipped with weapons much more similar to those mounted on spacecraft, only with a few more zeroes appended to the numbers.
Coda's armament is almost entirely grosswave beam cannons whose interaction with the atmosphere often result in floods of ionizing radiation all along the beam. It flies like a brick, basically can't fight in the air and only lifts off for ballistic jumps from A to B. Nowadays it is rarely deployed alone, mostly serving as support in the toughest fights, with newer machines like Knock Jericho and Kaiser Yukatan doing most of the fighting. It's kept afloat by its operating cost of ~24 billion USD-2022 annually, really cheap for a starkiller.
Arsenal Dresden is, much like all the others, not where its name implies. The exact location is five kinds of classified, but Axis espionage places it somewhere under the Alps.
