It seems as though dedicated server makes it more difficult to choose tracks, choose cars, kick/ban players, etc. since it all has to be done via command line where as the GUI version just takes a few clicks to do most anything. Also, running the GUI version doesn't really require many CPU cycles or resources. So, other than the fact that the dedicated server is a small download, is there any other advantage to running it over the GUI version? I really can't see any advantage to the text mode dedicated server at all.

Is there something I'm missing?

Dedi is absolutely free.

I beleive a 3d card is not required for the dedicated server.

cpu cycles

I run a few dedicated servers on my secondary machine, and play on my main rig. I can run as many servers as I want for free, but only one GUI server. The dedi is much less rescourse-intensive as well.