Also see: Effective C++ (by Scott Meyers) Item 23: “Prefer non-member non-friend functions to member functions. Doing so increases encapsulation, packaging fl

Also see: Effective C++ (by Scott Meyers) Item 23: “Prefer non-member non-friend functions to member functions. Doing so increases encapsulation, packaging flexibility, and functional extensibility.” The text has a lot more detail but that’s a brief summary. Folks just need to read the literature then this sort of knowledge would be in common use. One downside of language evolution is a lot of people focusing on new language features, etc, but then some of this older, important knowledge gets skipped over.