For me one of the lessons is don't mix and match GPS with an instrument approach which is based on "hard" radio aids.
I venture to suggest that if this a/c had not been equipped with GPS this accident would not have happened. That said I am of course aware that there are other threats associated with flying the "raw data" instrument approach.
It might have been better to fly the instrument approach from overhead DND using basic radio aids only with GPS as confirmation.