[juitpykyk]

And one day you'll unplug it and complain "why is the battery at 80%? It was plugged in all day. Stupid manufacturer. I will tell everyone to avoid this piece of shit"

The least losing move for the manufacturer is to always charge 100%.

[alexvoda]

Or you can actually explain the feature to users and let them choose and users can learn.

On my Lenovo laptop I have a toggle I can switch any time between battery saver mode(stay at 80%) and fast charging mode (charge asap to 100%).

If when designing products you never even let users choose to learn, you guarantee you will have a stupid user base. Stop endorsing stupidity.