From the other direction, coming from low-level languages: the other problem is that Rust's type system isn't powerful enough to express certain things that you, a competent C programmer, might be fully conscious of...and so you end up needing to fight the type system to get it understand something you're already aware of. To use a classic example, you can understand exactly how the lifetimes work in a doubly linked list but still find it more painful to write in Rust than in C.
Happy to see that it's getting frequent commits, would love to see it become more popular.
It's good in some cases, bad in others.
What’s the problem here in Rust?
It's only a useful tool that has some nice qualities in some settings. It's not some underlying truth of the cosmos, it's just a situationally useful way to do things.