Maybe for your use cases that’s OK, but there are many situations where the size and ease of upgrading provided by shared libraries is worthwhile. For example it would suck to need to push a 40+ GB binary to a fleet of systems with a poor or unreliable internet connection. You could try to mitigate this sort of thing by splitting the application up into microservices, but that adds complexity, and isn’t always a viable tradeoff if maximizing compute efficiency is also a concern.
In my understanding, you can’t interface with the C abi without using an unsafe block.
The main issue I have with rust is the lack of a rust abi for shared libraries, which makes big dependencies shitty to work with. Another is a lot of the big, nearly ubiquitous libraries don’t have great documentation, what’s getting put up on crates.io is insufficient to quickly get an understanding of the library. It’d also be nice if the error messages coming out of rust analyzer were as verbose as what the compiler will give you. Other than that it’s a really interesting language with a lot of great ideas. The iterator paradigm is really convenient, and the way enums work leads to really expressive code.
One specific example I encountered was ndarray. I couldn’t figure out how to make a function take an array and an arrayslice without rewriting the function for both types. This could be because I’m novice with the language, but it didn’t seem obvious. I ended up giving up after trying to dig through the docs for a few hours and went back to C++.