Why Casein Now?

So why casein now and not oil?  I think maybe I've come full circle, back way back in art school  (Ringling School Of Art) before oil paints.we were introductions to gouache and casein as the medium for our class projects and assignments for the first year.  The next three years fine art students used mostly oil, graphic artist stayed with gouache and casein as a rule,
When I worked as a illustrator gouache was always a go to medium. For the past 20 years I  have worked en plain air with oil or pastel, in recent years I rediscovered casein paint and the advantages it has over oil paints. Easy clean up, fast drying, coast and reworking.
Here are some website with more on casein and artist ...
http://gurneyjourney.blogspot.com/2013/04/casein-experiment.html, http://nathanfowkes-sketch.blogspot.com/.https://www.youtube.com/watch?v=ftpsi6RFrMc&t=3522s

Unlike  gouache, casein can be applied either in thin washes or thick brushstrokes,  As with any other paint, there are certain things that will ensure the best results with casein, such as working on a rigid surface, masonite coated with acrylic gesso and completely dry for several days.