> Passing things by const T& is always good, right? After all, you’re avoiding a copy! I find the tone strange. I understand that the author doesn't believe th

> Passing things by const T& is always good, right? After all, you’re avoiding a copy! I find the tone strange. I understand that the author doesn't believe the statement. But I've never met anyone for whom performance matters and believes this. So, who's the audience here?