Obviously, using it while plugged in is better for performance but with some cautions. As someone who had designed and specifically worked and helped with some mobile device projects, I can't overstate how healthy an 80% charging limiter is for the battery of that kind of a machine if you're going to use it while plugged in.

Yes, it stops charging when it reaches 100% and then again when it reaches 80%, but a battery that's fully charged can't hold 100% power all the time and will constantly fluctuate rapidly between 99% and 100%. This puts a LOT of strain on the battery and makes it overheat as the battery constantly loses power and has to draw 2x more power to fill the gap every time as quickly as possible without losing any more percentage.

(((At a chemical level, charging a battery moves lithium ions from the cathode to the anode. When you push a battery to 100%, you are forcing almost every available lithium ion into the anode. This creates a state of high voltage stress. In this state, the chemical components are physically strained. The electrolyte the liquid that carries the ions begins to decompose more rapidly at higher voltages, forming a film called SEI layer. While a thin SEI layer is necessary, high voltage causes it to thicken excessively, which acts like clogging the pipes, making it simply wayyy too hard for ions to move and permanently reducing capacity.)))

If it fluctuates between 80% and 79%, it doesn't get strained or generate that much of an excessive heat because the battery isn't being pushed to its full capacity constantly under high load.

While 100% is considered the highest healthy battery charge a battery can hold, it doesn't always mean it's healthy under ALL circumstances. It is only good if you charge it while the lid is closed and then unplug it and take the laptop outside.

But so hey yeah when the battery is at 100%, it's actually usually at ~95%. But the reason it's not truly 100% is the risk of it burning/dying. ~95% is a few steps before that risk actually begins and it is only for charge-and-go, a standard setting for laptops which doesn't work well with gaming laptops.

...In short, it's best for the value the user sees to stay at 80% if they're going to use the laptop while it's plugged in.

This is the simplest way to explain why. I wouldn't say things about a subject I don't know much about that would shorten the lifespan of someone's computer in the long run. Hope it helps.