There are certainly areas where idiomatic Rust needs to fight against the borrow checker. If that wasn't the case, things like `ouroborous` and `pin_project` wouldn't be as widely used as they are.
Day to day rust users shouldn't care too much about pin_project since the big use case for pin is handrolled futures and executors. Most folks just use adaptors from the futures crate and one of a handful of executors in the ecosystem.
I've never actually heard of that other crate. It looks like most of its downloads come from its direct/indirect dependents like glium. I'd say if you're writing self referential data structures you're not writing idiomatic Rust.
Got to disagree here, a typical use case based on my experience is a parser holding a &str as well as an AST that does zero-copy references into the string.
