Focus confirmation is great for chipped lenses. I often use fully manual lenses that don’t have an electrical connection. I also don’t shoot sports much, but for most things I prefer using the viewfinder and don’t want to be fiddling around with a right angle finder. Now if I’m shooting on a tripod I might be more likely to use the monitor, but besides better manual focus support, another big benefit to using manual lenses on mirrorless is that I have IBIS which means I don’t need the tripod as often.