The value in property based tests is that the original libraries (Quickchwck, both Haskell and Erlang) try to find the smallest reproducible error sample, and then display that sample to you.

And that (Quickcheck at least) has a bunch of primitive generators that you build your structures out of.

No idea, if it's doable in Rust. I just find it strange that it works on a stream of random bytes out of which you magically get some structures.