I think the one major use case for the high DR of the Alexa 35 is the ability to record fire with no clipping. It's a party trick really, but a cool one. It's kind of fun to be able to see a clip from a show and be able to pick out Alexa 35 shots simply because of the fire luminance. That being said, it has no real benefit to the story in any real way.
I did notice a huge improvement in the quality of my doc shoots when moving from 9-10 stop cameras to 11-12 stop cameras though. But around 12-12.5 stops, I feel like anything beyond has a very diminishing rate of return. 12 stops of DR in my opinion can record most of the real world in a meaningful way, and anything that clips outside of those 12 stops is normally fine being clipped. This means most modern cameras can record the real world in a beautiful, meaningful way if used correctly