As a fellow enjoyer of heavy/extreme music, I appreciate a well-written song in any genre, and I'd say her talents are far more along the songwriting vein. She's a reasonable musician, but her ear for hooks and her lyricism are far more remarkable than her musicianship.

If anything, you might like Cardigan. I've enjoyed metal and some rap most of my life, and I find that those are more about the lyrics than the melody (but obviously the melody matters). Cardigan is one of her best lyrical songs, IMO.