If that is true, what's the trade-off? There are no silver-bullets so if their approach didn't involve some potential "deal-breakers" Go team (or the ecosystem) would probably have offered a Go clone of it. Would be curious what they're doing there in Rustland..

I've only just started learning Rust, but from what I understand, the trade-off is that the type system in Rust is much more complicated, and thus harder to learn. Pointers have a concept of "ownership" and "borrowing", which can be more difficult to reason about, whereas in Go, you don't have to think about it as much--pointers are just pointers. It also makes the Rust compiler more complicated, which mean slow compile times. One of the main design goals in Go was blazing fast compile times.

Rust compile times are not due to the borrow checker. They are primarily due to optimization.