I have not found it useful during line op's.
More for playing around and seeing if you went direct where your great circle route would really be verses a your flight plan. For example, VHHH direct KJFK in the FMC will give you distance and initial bearing, but not much other info. Doing along track points at an interval will let you see where the great circle route really fall, how far north you really would go, bearings on each segment,etc.