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Optical chips dissipate way less heat and work way more efficiently, which more than just being good for power efficiency actually overcomes the main current limitation on processor power.
The main road block to Moore's law right now is power density- even if we crammed more transistors onto a chip, the heat dissipated by processors is such that they'd pass the thernal noise limit and stop working. Working with optical components sidesteps this issue.
Optical circuits are also a primary component of many quantum computer designs.