What are the use cases for god Cyclius, Spirit of Ages?

Here's Cyclius, Spirit of Ages:

Cyclius' effect is:

CpS bonus fluctuating between +15% and -15% over time.

and the only thing his placement in Pantheon (Diamond/Ruby/Emerald slot) changes, is how fast that fluctuation cycles (every 3/12/24 hours, respectively).

All other gods directly increase cookie production (CpS/milk/wrinkler bonuses) or enable you to do so (Golden/Wrath cookie bonuses, discounts). However, even looking at Pantheon's page on Cookie Clicker's wikia, the net effect of Cyclius on CpS is 0%.

What am I missing? Is Cyclius supposed to be a god you have to constantly monitor and unslot before negative bonus cycles over?

Cyclius' bonus is affected by the current time of day, not how long it has been since you slotted him. So the way to use him is by slotting him when he's providing a positive bonus, and unslotting him when he's providing a negative bonus.