tl;dr – you don’t need it
I personally do not like the idea cruise control on a motorcycle. Many long-distance riders will disagree with me on this. While my speed may not be locked in at a consistent 80MPH, my head is always in the game. Highway hypnosis is a real thing and doing everything you can to stay focused on a 12 hour stretch is, in my opinion, the responsible thing to do. I do agree it can get painful after too long, but that means you should probably stop, stretch, pee, hydrate, gas up, self check. There are other comforts I will agree one should upgrade to, but I think this is one place I would stick old school and keep that wrist twisted.
If you are riding long distance without cruise control, I do recommend finding pace cars. On any highway you will find another car going approximately the speed you prefer, just fall in line behind them and let their cruise control do the work for you. It also frees up a little brain space for managing other things. We all have limited mental capacity [I know that does not sound fun]. If you take things out of your mind that are easily placed on a trusted source or have little value, you free up that valuable space for more important things. So, let a pace car do the speed management and you can enjoy more of the ride, or think about the next hydration stop.
Moto Kinder 