[Arnavion]

They probably didn't mean replace wholesale, but that `ls` in a shell is a wrapper around the underlying coreutils `ls` with some extra flags by default. Eg:

    $ (. /etc/os-release; echo "$NAME:$VERSION_ID")

    openSUSE Tumbleweed:20210121

    $ command -v ls

    alias ls='_ls'

    $ grep -A6 -B1 '_ls ()' /etc/profile.d/ls.bash

    bash|dash|ash)
        _ls ()
        {
            local IFS=' '
            command ls $LS_OPTIONS ${1+"$@"}
        }
        alias ls=_ls
        ;;