Thanks for the ask, I love this topic so much!!! It’s interesting why and how Zuko became a dual wielder (other than it looks badass - which in a cartoon is a good enough reason, I guess)

Zuko trained under Piandao, who told Sokka that his sword must be an extension of himself. For Sokka, that meant choosing an unusual material, thinking outside the box. For Zuko, it meant choosing a weapon that requires balancing his two sides and learn to see it as part of the same whole.

Much of Zuko’s arc is about finding this balance inside himself - he’s full of duality: he’s the scarred boy and the perfect prince, he’s the son of Ursa and the son of Ozai, he’s a Fire Nation crown prince and he’s an outlaw dressed as a water spirit, he carries both Sozin‘s and Roku’s legacy, he’s a pursuer and a fugitive, he lives both a privileged life and utter destitution, he’s a thief and a vigilante, the list goes on.

I think finding this balance in his fighting, understanding that the two weapons are not separate, but the part of the same whole, helps him process and accept this duality in himself.

Also, it’s interesting that Zuko doesn’t have one set of swords he’s attached to - he cycles through at least 4 pairs of swords in the series, indicating that the weapon matters less than who wields it. It’s a tool that can become the force of good or evil, of attack and defence.

As for fighting style, it definitely is more dynamic than a single sword - it requires constant movement, which fits Zuko so well; he never stands still, he’s always moving in some direction and makes things happen. It also complements firebending really well. And whenever Zuko gets stuck narratively, the swords have a prominent role in finding a new direction:

When Zhao captures Aang - Zuko has to balance his loyalty to the Fire Nation with his mission;

When he’s a refugee, he has to balance survival and honour,

In Zuko Alone, he has to balance Lee, the refugee with Zuko, the prince; the swordsman with the firebender,

In Ba Sing Se, he has to attack Jet to defend Iroh, then he has to choose between being the son of Ozai or of Iroh when he frees Appa,

When he returns to the Fire Nation, he finally figures out his ultimate dilemma - having to cut his ties with his father and the Fire Nation to help save the world (and the Fire Nation in it)

And the last time he uses the sword, it’s not to fight, but to open the door to finding finally peace, balance and mastery in his bending, so he can become the teacher Aang needs.

These are some of the most iconic moments of Zuko’s journey. I think in his case, the sword mastery itself is a part of his healing process, of unlocking his potential in firebending, of finding his own path, and it’s a tool that allows him to do intuitively what feels right, before he is there in his conscious thinking. He can go against the Fire Nation, free the Avatar, defend Earth Kingdom folks, free Appa before he is able to do it openly. Sword mastery helps him to sort out his confusion, to become whole again, to achieve mastery of himself. It’s a way for him to work through the chakras, to break down the illusion of separation and cut his attachments. And as such, the dual swords are perfect for him.