I think the calls to std::move in those specific examples are due to optimization flags not being passed to the compiler invocations on godbolt. That being sai

I think the calls to std::move in those specific examples are due to optimization flags not being passed to the compiler invocations on godbolt. That being said, I've definitely heard of std::move in the wrong places preventing optimizations (e.g., std::move on a return statement can (will?) inhibit copy elison), but I'm not familiar enough with the finer details of C++ be able to tell you why.