whats the point of using optimized battery charging if macbooks cannot get overcharged anyway

I heard using optimized battery charging will increase battery lifespan. it works by delaying the charge if its past 80%. it says it will help conserve battery life because keeping the battery charged at 100% for a long time is bad for Macs.

the problem is, I don't want to waste my battery cycles by turning this on, since it also contribute to the battery life. I keep my Mac plugged in all the time since it is recommended by everyone and apple use lithium ion batteries that cannot overcharge.

so, what's the point of using this optimized battery feature and trying to keep it at 80% if the battery won't overcharged 100% anyway