CDs and DVDs are not flash drives, they only contain the data burnt on their surface.
The CD drive’s most important function is to read (using a laser) or write (using a laser) small marks on the shiny layer of plastic coating on the inside of discs called “tracks.” This writing can also happen at two different speeds, a normal speed which takes about 150 seconds to burn an entire disc’s worth of music onto it at 16x, or fast speed which takes less than 4 seconds per disc at 24x.
CD drives are used for storing data, not transferring it like USB sticks. A digital camera may output images stored on its memory card via a connection controlled by your computer’s CD drive.