Without knowing details such as the number/type of gate/transistor equivalents there are, the cost of manufacture, the power requirements and so forth it isn't that relevant to "CPUs and overclocking".
It isn't useless if it just used like the example for a frequency comb, or filtering or the like. But let's find out if it can even implement a 6502 before we make shocked face reactions. It probably will have very different roles - most likely roles that involve incoming and outgoing fiber optic connections where the speed is less important than avoiding wasteful transitions to/from electrons.