Hence the term "light tank".
A light tank's job was to serve as a big gun for rushing infantry. Light tanks were designed to protect armored infantry fighting vehicles, and to serve as a fast-moving lightly-armed spearhead.
When you plan a static defense, you don't put all your heavy shit on the front lines. You layer it. Behind your obstacles and mines, you generally put mortars, light field artillery, heavy fixed machine gun emplacements. Stuff that can chew through the infantry that tries to breach the obstacles.
That's the stuff a light tank is designed to fuck with. Just like it's name, the Lightning was probably (I'm not a dev or banging a dev) designed to be a fast-attack weapon. Just enough armor to scout around, just enough weaponry to make life hell for infantry and light armor, and the most important feature- Galaxy-portable.
There is no substitute for an accompanying gun platform when you're an assaulting infantryman. The only thing better to bring would be the Marauder, and since you only get one if you're TR or a hacker, the Lightning would be my next best choice. I've driven the Thresher, and there's a reason you don't see too many in the game. THEY SUCK. I've also driven the Enforcer. And while the Firebird missile is a good weapon, it doesn't have the versatility of the Groundpounder mortar. Hence the Lightning.
So in other words. In the hands of an intelligent person with a degree of tactical know-how and a set of balls, the Lightning makes an excellent addition to an assault.
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