I'm basing my figures for max, min and average speeds as displayed by my bicycle computer. I also mentioned a loaded trailer to demonstrate that I'm actually slower than the majority of cyclists here because they're not towing around extra weight like I am (meaning their average speeds are higher than mine and they can maintain higher speeds when going up hill compared to me).

Also if I were to maintain an average speed of 8 mph, then my commute where I pick up my kids in different locations would take me nearly 2 hours as opposed to about 1 hour and 15 minutes. So speed matters if you want to complete the ride in a reasonable period of time.