Apple believes that the balance between aesthetics and functionality is hard to achieve. “Some aesthetically pleasing materials may not be sufficiently durable to include in a device housing or other components, and other aesthetically pleasing materials can interfere with the advanced functionality of the electronic device.”
Transparent keyboard with glass keycaps
Therefore, Apple wants to use glass as the top external surface which can be more durable as they are less scratch-resistant. Apple also said that these keycaps will be advantageous in situations where the keys are backlit or side-lit due to their transparent or translucent nature, leading to a more pleasing appearance.
Glass keyboards: Is it a feasible idea?
Gizmodo also suggested three different kinds of glass that Apple may use — annealed glass, tempered glass, and laminated glass. However, all three are not indestructible and still stand a chance to cut the user’s fingers when broken. But then again, Apple’s main objective is to create transparent keycaps which can be done with materials other than glass. Other options like acrylics or resin may sound safer as compared to the usage of glass; we won’t want to watch our fingers bleed all over the keyboard if there’s a mishap.