Yes, its a cool -looking- feature.
However, other than giving you situational awareness of whether an airport is close to your ring while everything is ticking along without problems , shouldn't all of us -know- our approximate glide target with our eyes out of the cockpit?
I don't know about everyone else, but I'm going to be too preoccupied going through an emergency checklist and looking -outside- to find my best options to put the aircraft back on the ground. I wont be looking down at my kneeboard.
That being said, it would be a good training tool to give you an idea on what your glide circle is when you are practicing. Just don't rely on it.
My 2 cents. (Maybe I should just drink some coffee

)