How effective is a katana?

I'm curious to know, just how effective is a katana in practical use? Is it truly the legendary weapon it's made out to be, capable of delivering swift and precise cuts with ease? Or is it more of a symbol of Japanese culture and tradition, rather than a practical tool for combat or self-defense? I'd love to hear your thoughts on the matter, as a professional in the field of finance and cryptocurrency, but also with a keen interest in the history and effectiveness of various weapons.