In [AXS. 2010] Michael Schmidt wrote “I prefer black and white photography because it guarantees the viewer a maximum amount of neutrality within the limits of the medium. It reduces and neutralizes the coloured world to a finely nuanced range of greys, thus precluding an individual way of seeing (personal colour tastes) by the viewer.”
In combination with overcast skies diffusing light, removing shadows and producing a flat reduced depth and contrast image, the image is simplified, easier to consume and comprehend by the viewer.
In considering this aspect of light and photography I think about my own experience and think ( confess even ) that I feel more relaxed, comfortable and confident when taking shots and the sky is overcast. Classically good exposure is easier to attain and dynamic range much reduced. A good quality outcome is nearly always more likely in this case all be it that drama may be harder to achieve. In viewing the images in https://www.prixpictet.com/portfolios/consumption-shortlist/michael-schmidt/ drama does not seem to be what Schmidt is looking for.
Bibliography
AXS. 2010. Michael Schmidt: Thoughts About My Way of Working. [ONLINE] Available at: http://www.americansuburbx.com/2010/10/michael-schmidt-thoughts-about-my-way-of-working-1979.html. [Accessed 5 May 2019].