USB ports are much more common than CD and especially DVD burners, so USB Flash Drives will work with more computers than a CD-Rs or DVD-Rs. Also, the process of uploading files from your computer to a USB Flash Drive is much faster and simpler than burning a CD or DVD.

Additionally, USB Flash Drives act like portable hard drives to which you can add and delete files as many times as you like. With CD-Rs and DVD-Rs, you can only add data once, and you can't remove data once it's burned onto the disc.