The following is a video showing how an image is captured in a digital camera and how fast memory cards and card readers can help to speed up the process. The video is posted by Lexar Media, Inc., a subsidiary of Micron Technology, Inc.
If you are still connecting the camera directly to the computer to transfer the photos, you should consider getting a card reader. Personally I found it is a lot more convenient to transfer from the card using a card reader. I found it difficult to balance the camera on my desk with certain lens mounted. After a long shot, the battery in the camera may be low. You may have to charge it up before transferring the photos. After transfer, you again have to deal with the battery in the camera that is not full. With a card reader, the problems are solved. After getting back from a photo shot, I simply pull the card out of the camera and put in the card reader to start transferring the photo. At the same time, I pull the battery and put in the charger.