What is Material Design?
Basically, it was born as an attempt to combine the best elements of flat and skeuomorphic web design trends.
Flat design is a minimalistic approach that features two-dimensional illustrations, bright colors, crisp edges, and clean space. First of all, it emphasises usability. However, many designers consider flat design as a step back because it comes with icon-like, too simple images. There are several factors by which users determine if the element on the screen is clickable: contextual text (short phrases or words that are perceived as menus), and traditional markers (embossed buttons, underlined words, ets). Flat design often ignores them, which can negatively affect usability.
Skeuomorphism portrays the real-world elements online. In other words, skeuomorphic pictograms, icons, and buttons resemble their appearance from reality. It was a great solution five years ago as its real-life resemblances were familiar to most people. Moreover, skeuomorphism is ideal in terms of UX design. However, in terms of UI design, it comes with distracting and unnecessary details. After mobile platforms have evolved, skeuomorphism tended to interfere with loading speed and adaptability. Designers started looking for an approach towards simplicity and unification.