system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did the sword become so popular?

The sword (or some version of it) is everywhere. It's in video games, movies, books and throughout history it seems that the sword over most all other weapons retains some sort of use even after they become obsolete weapons of war. So how did the sword become so popular? Were there other weapons that were more popular in different periods of history for various purposes? Does the use of armor lessen the popularity of sword use?
gpt
The sword is a side arm which meant that it could be carried in normal daily life, and it would often mark the wearer as landed gentry who might kill you for dishonoring him. Dueling with swords was popular long after the sword itself became obsolete. It was a status symbol for thousands of years and when things are symbols for that long it's hard to get over them.

As side arms go the sword is more or less perfect. Because the center of gravity is close to the hand the sword allows much freer and faster motion than other weapons such as the axe. One could argue that axe plus shield is about as good as sword plus shield but a lone sword would almost certainly defeat a lone axe.

Sword of course are not terribly useful against armor and that is why the main weapon in the middle ages would be pole arms. But you can't walk around town carrying a halberd. Swords could still be useful enough against most armor if you could use it as a lever or get into weak spots.