system
Given the following post, respond as if you're commenting on Reddit:
human
[Metal Gear] What are Metal Gears, and why are they so important to the story?

From what I understand they're just bipedal tanks, what makes them so important?
gpt
Metal Gears' primary function isn't to be a tank or anti-personnel weapon, but to be a mobile nuclear weapons platform.

The theory is that by being bipedal/walking machines, they can traverse terrain that is impossible for wheeled vehicles to cover. Imagine how terrifying a walking nuclear missile silo would be; that's basically a metal gear in a nutshell. A devastating weapon that could be anywhere in the world, that is highly mobile.