Brainwaves are not timed fetch/execute cycles like computers but that doesn't mean there's not anything to this comparison.

Computers are built from the ground up on timing. Perfect sequentialling is required for computers to function. One thing happening out of order will shut the entire system down (some exceptions). Neural networks (even when simulated in software) don't have that strict ordering requirement.

Timing of networks in the brain allows for more efficient messaging with other networks. This results in faster computation and lower energy consumption.