I don't like doing this as you lose all your via points.
For example I sometimes plan certain stops for Coffee / Lunch / Viewpoints / Attractions etc so with a track it will navigate you right past them.
As stated I also like to use them for timings, if I have a coffee stop up next I can set the arrival time to next destination to see how long until next stop, also handy in a group with comms as all your bikermates will constantly want to know "when are we stopping"...
...And I tell them if they get lost / drop behind then unless they are in trouble to carry on and meet at the next stop point, and if diversions, weather or something else really buggers up your morning you can re-start the route and ask it to start from say the Lunch stop, so it will take the fastest route using main roads to that point rather than your planned route along goat tracks, which you no longer fancy in the rain, where you can then continue on the planned route if you have made up enough time / it has stopped raining.
I do however always show the Track on the screen, which gives away if the XT is diverging from the original planned route, if everyone has a Garmin (or something you can show route and track at same time) this can help avoid people taking slightly different paths - regardless of waypoints being every mile or two, in towns and cities different devices will often take a slightly different paths, especially in towns and cities where there can be multiple paths between two waypoints of similar distance and times.
