Easier, lightweight syntax for shell-like pipes, command execution and catching stdin/stdout/stderr.

Something like Perl's IPC::Run.

Also, more shell-relevant stuff in the default distribution, so that one doesn't need to care about any modules (which is the primary reason for using bash or even sh, those are installed practically everywhere along with at least coreutils and stuff).

But the sister comment clarified it in another way, so this maybe irrelevant.