Death Wings? Hmm... A bit over zealous for a DM in the Keys, where the diving is mostly easy shallow reef dives. I'd laugh in that DM's face. She probably has a long resume of dive experience to back up her boldness?
How many people have actually died because of their fin? Hmm...
To answer the OP. Use whatever fins work for you...
Yeah I thought it was sort of odd... she quite literally sat me down at a table by the dock and started with "we need to talk about your equipment...." I could have understood it if I was a student but I had close to 70 dives under my belt by that time. I wasn't offended because she seemed to be genuinely concerned with my safety but it sure made my wife who bought them for me as a father's day present feel like heel.