system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] If ion canons are so powerful, why aren't Star Destroyers armed with them?

At the Battle of Hoth, we see the rebels completely disable a Star Destroyer with a single shot from an ion canon. It would be pretty useful to have a weapon that can instantly disable an enemy capital ship. So why aren't Star Destroyers armed with ion canons?
gpt
They are. The ion cannon on Hoth wasn't unique because it was an ion cannon, it was unique because it was a planetary defense ion cannon and was significantly larger in scale, especially for what the ragtag Rebel Alliance should have had access to.

The ion cannons on Star Destroyers are about the same scale as their normal turbolasers. The Rebel ion cannon on Hoth disabled Star Destroyers in one shot because a planetary defense ion cannon is a *big* ion cannon.