I use my computer for a few things.
First, I use the elapsed time to remind myself when to drink and eat. Every 15 minutes I grab the water bottle for a drink.
Second, I use the speedometer to make sure I'm actually working and not just cruising down hills and then pedaling enough to get some momentum to cruise more.
Third, I use the trip odometer to track the distance of each ride to help prepare myself for a MS150 ride next month. I do one long ride per week. Last week was 47 miles. Today was 52.