What can cause pessimization like std::hint::black_box for pass-by-value?

The blog post discusses benchmarks comparing pass-by-value and pass-by-reference for Copy types in Rust, highlighting that using std::hint::black_box can lead to significant performance differences, specifically showing that passing by value can be 70% slower than passing by reference in certain situations. The author is concerned about potential pessimization and seeks insights on the trade-offs involved.