Traditional artworks have two elements in common: it can be touched (made of physical materials) and it is “one of a kind" (can’t be copied without recreating it). Traditional artworks can be created with a variety of mediums and tools, including drawing, painting, and sculpting.
Unlike traditional art, digital art is not bound by the limitations of the material world. You can get all the colours the human eye can see, change the vividness and brightness, and erase without a trace, all via a graphics tablet and stylus.