It seems that for the best performance you could simply choose the fastest model in each category.why isn't this method a good way to choose a CPU?

Choosing the fastest model in each CPU category isn't always the best method because performance can vary significantly based on specific workloads and use cases. Factors like power consumption, thermal management, price-to-performance ratio, and compatibility with existing hardware also play crucial roles in determining overall effectiveness. Additionally, benchmarks may not reflect real-world performance for certain applications, making it essential to consider how a CPU will be used rather than just its raw speed.