A lot of people strive for something that is simple (not like Rust, and I am not only talking about the borrow checker) and explicit ("debug your program, not your knowledge of the language) but also doesn't bear the historical cruft and idiosyncrasies of C. The fact that it can integrate with C code means that if you are already using C you can adopt it incrementally, plus it works as a build system and cross-compiler and I believe a package manager too.

So to sum up : A powerful C without the quirks that manages to keep things simple but is also a batteries-included experience with a smooth adoption path. What's not to love ?