> If memory management is already resolved with the borrow checker rules
Even in standard Rust, this only applies to a subset of memory management. That’s why Rust supports reference counting, for example, which is an alternative to borrow checking. But one could make the case that automatic garbage collection was developed specifically to overcome the problems with reference counting. Given that context, GC in Rust makes perfect sense.
If memory management is already resolved with the borrow checker rules, then what case can make you want a GC in a Rust program?