Remember, you cannot jump back unless you have already jumped ahead in the guide because you cannot see something that had already came on (50 hours ago for example) but only from the present on into the features. It allows you to jump around in the guide without having to scroll through it all the time.
With the 7100/7200 Dishplayers I liked the search feature functionality of being able to see all the shows on one particular channel when you did a search for that channel. That would be easier than having to jump all around the guide when you want to see what is on one particular channel.