Yes. In the end it is usually total wall time of the critical path that matters unless there are special considerations like power consumption or heat generation, etc.

Not the same thing, but CPUs are designed to optimize different things too. I know I have often had laptops that were faster for single threaded tasks, but my engineering workstation has typically had way higher throughput for a parallel work load. Say nothing about compute clusters. Lot of these things about single threaded and parallel fairly common.

There also tends to be fairly expensive setup and sync steps related to highly parallel stuff like MPI or GPUs, though sometimes less so in the case of say vectorization or threading.

Thanks, interesting.