I can't give you just one selling point, because Rust has two main competitive features, and it's hard for me to say which one is enticing FreeBSD more here: 1

I can't give you just one selling point, because Rust has two main competitive features, and it's hard for me to say which one is enticing FreeBSD more here: 1. Rust has a more modern sense of computer primitives than C does. For example, C has the char-short-int-long-long long set of types which correspond to 8, 16, 32, and 64 bit integers in practice (and yes, 5 types for 4 sizes), whereas Rust has u8/u16/u32/u64. Rust also has a builtin slice type, which is a desperately needed notion of pointer + size of array, and C's lack of such type has proven to be the source of much malware. The standard library is also somewhat richer too, you have better support for things like threads or networking than C/C++ does. But note that Rust is still like C in that it has a very thin runtime layer, and can also go a step further and have "no" standard library at all, which is necessary in several contexts. 2. The borrow checker. Effectively, use-after-free (or any other lifetime issue) vulnerabilities become compiler errors, and even many kinds of data races are also turned into compiler errors. Also it can do things like make iterator invalidation issues a compiler error as well.