Why was the katana bad?

I'm curious to know, what made the katana so problematic? Was it the design flaws, the materials used, or perhaps the way it was manufactured? Was it ineffective in battle, or did it pose a risk to the user? I'm intrigued to understand the reasons behind its shortcomings and how it fell short of expectations. Could you elaborate on the issues that made the katana a less-than-ideal weapon?