WHY DO CPUS HAVE MULTIPLE CACHE LEVELS?

Summary from the TLDR Web Dev newsletter

CPUs have multiple cache levels to balance speed and size. The L1 cache is small and fast, primarily for storing frequently used data at the byte level. The L2 cache is larger but slower. It deals with cache lines (groups of bytes) and handles most communication between the CPU core and other components. The L3 cache is even larger and slower, serving as a shared resource for multiple cores and handling less frequent requests.