It just seems strange to me to see  "user x" have a whole page of short logins in/out/in/out but containing no comment.  Is there something I'm missing about using, for example, the file request channel?

Those people usually have 'flaky' internet connections. You can turn off seeing the join/leaves. In a channel press the 2 gears button to the right of where you input text into the channel. Now unselect join/leave.