Clarification on passing by value

Hi all, on my journey to learn zig I was a bit confused with all the discussion around the pass struct by reference or value. My main point of confusion came from reading this discussion: Pass by value semantics. While learning the language, I tried to follow as closely as possible all the advices on the 0.16 documentation, but from the discussion above it seems that it is not quite updated. When is it advisable passing a struct via value or reference? Coming from C++, I was prepared to pass ...