Why is it meaningless? It tells you how long a clock cycle takes, and you can look up instructions per cycle for relevant calls. I admit the picture for what makes a fast CPU is highly application dependent and has a lot of variables to consider, but I don't think it's meaningless.
As I stated, CPUs don't actually run at the base clock rate. They idle well below and under load they boost above it. How much they boost is of course architecture, load and temperature dependent, but it's generally a fair bit higher than the base clock.
Meaningless because (adequately cooled) modern desktop CPUs mostly run near their boost clock in single threaded loads and somewhere between base and boost in multithreaded.
It does not tell you how long a clock cycle takes. It tells you how long a clock cycle takes when the CPU is massively loaded on all threads, in adverse thermal conditions. If you have better than average cooling, you will never see the base clock under load. If you are running just a single thread, you will always boost to Fmax.
