My reason for traveling slightly faster than the flow of traffic is this:
On divided highways the past few years, my experience has been that the most risky maneuvers by far are people traveling faster than me, behind me in my lane, coming right up to my rear bumper and then swerving into the next lane to pass, narrowly missing me. It has happened more times than I can count. Staying slightly faster than the flow minimizes the number of these incidents. It's easier to observe what's happening ahead than what's happening behind.
On divided highways the past few years, my experience has been that the most risky maneuvers by far are people traveling faster than me, behind me in my lane, coming right up to my rear bumper and then swerving into the next lane to pass, narrowly missing me. It has happened more times than I can count. Staying slightly faster than the flow minimizes the number of these incidents. It's easier to observe what's happening ahead than what's happening behind.