I've also gleaned some insight into my general disposition over the least year from the playlist. I can tell exactly when I was in a "mood" or a rut... When I was listening to lots of angry music, that was reflected in my suggestions and my picks. And when I was opening up and relaxing—that also shows through the playlist.
I'd say that if your taste in music has a wider range and not specific to a single genre, your Discover Weekly will be a lot more rewarding. And also, if you rotate through musical moods like seasons where some tastes come and go over the course of a month or two, your Discover Weekly will support that and help you indulge in the mood of the month.