I reckon cruise is very useful. As I get older, my hands hurt more. I'm seriously considering adding an aftermarket Veridian cruise control to the 690, so that they hurt less, and most importantly, I can continue enjoying riding.
Not to mention that cruise enables consistent speeds, no more happily tooling along, glancing down and realising you've been enjoying yourself so much that you're 30km/h over the limit - not me, I would never, but...