If you look practically, focusing on death rates doesn't really paint the whole picture. As someone who works at a hospital I can tell you that when enough people get it, the floodgates will open, which then becomes a problem for anyone else needing certain types of medical attention, because full is full. If you let that go it's course, the death rates will increase, because treatable emergencies will not be treated anymore. They have actually made guidelines here to choose patients over others, as a result of the first wave. And the burden it put on healthcare is the entire reason why so many places went into lockdowns in the first place. All the other outbreaks we are familiar with over here just don't do that.
Furthermore, many people are ill for a long time and a whole lot, even mild cases, still have issues months after the fact. Myself included, though thankfully mild. Those hospitalised even have a chance on permanent lung damage, never being able to breathe normally again. Especially the ICU cases, given their scarring.