What is better, cat 5 or 6?

As a cryptocurrency and finance professional, I'm often asked technical questions, but let's pretend I'm a questioner for a moment regarding the topic of network cables. So, here's my simulated question: "I'm setting up a new network infrastructure for my financial services firm, and I'm torn between choosing Cat 5 and Cat 6 cables. Could you help me understand which one is better? I've heard Cat 6 offers higher bandwidth, but does that make it inherently superior for all use cases? What are the main differences, and which would you recommend for a secure and reliable financial network?