That's a fair point, although there is a simple solution in Rust (and other RAII languages) to use heap allocation if what you want is moving big chunks of data

That's a fair point, although there is a simple solution in Rust (and other RAII languages) to use heap allocation if what you want is moving big chunks of data (so only the pointer is moved) or in case you really want copies, reference counting (Rc/Arc in Rust).