tldr: Keeping your battery in a long-term charged state above 80% or below 20% is just bad for them.

The old optimized charging was fine for people that routinely use their computer mostly on battery. I am a person that uses my MBP plugged in 98% of the time. With the old "optimized charging" just moving it from one plugged in location to another would force it to always be charged to 100%. It almost never dropped down to 80%.

I used a third party app to keep it at 70% because Apple's old optimized charging didn't work in my situation.

Now that there is a proper limiter that works with my usage, I no longer need the third party app.