I often pop the route into the GPS, but leave it on the present position page. To give the student some confidence in his/her pre-flight calculations when they're between visual fixes, I'll flip it to the navigation page and show them "Look - how your good computer work and flying are! The GPS shows you spot on track and agrees with your ETA. Good work, well done!"
It also proves to them how their Standard Closing Angle correction has got them back on the original track.
A useful way of 'rewarding' their efforts. But just to use it with no real training objective would be a bit soul-destroying for the student.