I think the size of linked binaries and simplicity were always the main features?
I haven’t dug into why, but for unknown-linux builds on x86, Rust binaries have been substantially smaller on musl than standard dynamic linking to glibc, for me. No idea if I’m doing something wrong or if the handful of cases I tried were all special in some way.
Yeah... I've recently had a chance to compare how fgets is implemented in both GNU libc and musl, and, well. With glibc, it was a challenge to even find where the fgets's code actually is.