I use average speed when recording my miles but there are so many factors that are more important on a per ride basis. I may have a fast average on a Monday night group ride with upwards of 10 strong riders but I know I didnt do all or even half the work. The terrain, wind and company are going to strongly influence the average.

However, I can track and compare my averages month to month and yearly. I do like to see what months I tend average more or less. Stuff like that. I have noted that my overall averages have increased every year since I started riding.