Material Design creates systems of design to be implemented into websites that increase functionality and an easier user experience. I really appreciate the explanation behind each choice in color system, iconography and symbols, and type systems to create a more visually appealing site. It is also interesting to read about how changes in shape can convey different types of attention (retail, brand, personal site, etc.), and how different color schemes are capable of saving battery and causing less eye strain.
The Typography session was a crash course in choosing appropriate sizes and combinations of typefaces similar to what I learned in a class a few years ago. It is helpful to see examples of "good" and "bad" design to be able to make your own choices about what type of font combinations will work best for your particular style if you are hoping for readability and truly getting a viewer to obtain the most information they can from the site or poster.