I mean, my man there is plenty of historical evidence of it's use that make's it common. It was used throughout history in various cases, just because it wasn't used on the battlefield does not make it uncommon. It just makes it impractical and that's okay. No one is saying otherwise lol. I'm perfectly fine with them implementing this because it was realistic, even if impractical.
It should absolutely be in the base game if the game allows for it because it's a form of combat.
Yes there are because it's historically accurate and was used,
no matter what scenarios it was in. You can't say it isn't historically accurate when there's clear proof throughout history, lmao. Nor can you argue against it's inclusion unless you just don't like dual-wield, personally, and that's fine. It's your opinion but that doesn't mean it shouldn't be included