Yes, for single-threaded benchmarks Geekbench 5 and 6 are very well correlated with the SPEC scores and with other single-threaded CPU benchmarks.

On the other hand, whether the Geebench multi-threaded benchmarks are meaningful is questionable. Especially Geekbench 6 has a very poor scaling to many threads, which shows results that are quite uncorrelated with many practical workloads.

Moreover, the multi-threaded benchmarks are too short to reach a steady-state, so they show extremely optimistic throughputs for CPUs with poor cooling, like those from smartphones and laptops. Thus with Geekbench many smartphones and laptops appear to be competitive in multi-threaded performance with desktops or servers, while in real workloads their performance would be pathetic (because as soon as they would overheat, their performance would drop drastically).

Like any benchmarks, Geekbench can be gamed by CPU vendors.

For example, because already the older versions of Geekbench included secure hash computations, the Arm Aarch64 CPUs obtained good scores, because since 2012 they had special instructions and hardware for computing SHA-1 and SHA-256.

The x86-64 CPUs did not have such instructions, so they had bad scores. This prompted Intel to add a SHA ISA extension, but they added it only to the Atom CPUs, because only those competed with Arm CPUs and people compared their Geekbench scores.

For many years, among the Intel CPUs only the small and cheap Atom CPUs had SHA instructions, while their big and expensive desktop/laptop/server CPUs did not have SHA instructions, because at that time nobody compared their Geekbench scores.

This has changed only after the launch of AMD Zen, which included the SHA extension. Then, eventually, after the years during which Intel failed to progress beyond the Skylake derivatives, Intel finally added the SHA extension to all its CPU series, starting with Ice Lake, and since then all the x86-64 CPUs have it.