Displays are not so bright when the sun shines directly into most of your room. 
Especially the smartphone displays’ brightness values mean absolutely nothing if you have to pull out your phone while walking on a sunny street.
As for the studies, I’d take them with a huge bag of salt. Especially breast cancer closely correlated with artificial outside lighting? Very oddly specific and I’d bet they got to this conclusion since they didn’t have big sample sizes to work with.
Still, I am on their side – I am very sure artificial lighting is damaging for us. But I also believe there are ways to severely mitigate the effects, f.ex. I know people who prefer red light during most of their evenings and have reported feeling more relaxed and in a better mood in their free time at home.