Whether `ls` is the BSD-derived ls that is shipped with MacOS or GNU ls has effects on how well Dired works, and a similar thing applies for M-x grep and M-x compile, but coreutils has no bearing on whether Emacs can successfully draw a window (frame in Emacs terminology) on the screen that is functional enough to, e.g., echo the user's keystrokes.

I know that because I used to have GNU coreutils installed on my Mac, then I was a Linux user for a little while, and now I am back on a different Mac, but I have yet to bother installing GNU coreutils on this Mac and I notice no difference. Also, I've been using Emacs since 1991.

But yes, I am almost sure I had GNU coreutils installed when I had the very pathological problems with FSF Emacs circa 2012.