Flat Shoes are shoes in a wide variety of different types of styles that they have no heel serving to add height/elevation to the wearer. Flat shoes may have a very small heel height; however, generally this will be 1/2" or less.
About Sequins:
Sequins are small, flat, round-shaped pieces of a shiny plastic or metal, which are generally sewn onto clothing or footwear to reflect light and add shimmer.