Earlier quoted context omitted.
Especially in prototyping you can mostly .clone() everything, and stop worrying about any lifetime problems.
Lots of deferred pain for when you productionize.
From personal experience of Rust projects in production, you can get by with cloning for a long time, and optimizing later is not too big of a pain in most cases. Performance problems due to excessive cloning are also very obvious in code and easy to profile for.