That weird metal country always felt like such a weird detour to me, honestly. The Kage Summit arc was already so packed, and then we just... go to a place full of samurai? It wasn't my favorite part. But looking back, I guess it served a purpose as a truly neutral ground. Konoha or any of the Five Great Nations couldn't host that meeting without it being a power play.
What I find more interesting is the thematic clash it introduced—samurai vs. ninja. It was a blunt reminder that chakra and ninjutsu aren't the only power system in their world. Seeing them use pure kenjutsu and willpower was a cool contrast, even if the arc itself dragged on a bit. It expanded the map beyond the hidden villages, which was needed for the war to feel truly world-spanning later.