(1) Desktop clients used to be faster and more efficient than using a web interface, and probably still are in most cases. However, Gmail is impressively snappy

(1) Desktop clients used to be faster and more efficient than using a web interface, and probably still are in most cases. However, Gmail is impressively snappy so I don't think it applies in that case. (2) You can do things with a desktop client that you can't do with a web interface. That includes sort by subject and sort by size. (3) Desktop clients can have real folders, which Gmail doesn't. (4) Works off-line. This is still useful, though not as useful as it used to be. (5) Easy to backup. Easy to automate backup.