I love this feature on my 15 Pro Max. I have no doubt that the only reason I've managed to maintain perfect 100% max capacity is because I've always had the 80% hard cap on charging enabled since I got it on launch day last September. Eight months and counting without losing even 1% of overall health is a testament to the power of this little feature. And being a Max model, I can easily sacrifice the 20% battery life and easily get well into the next day on a single charge, if not the entire next day.