Have you ever had a set of those?
I put one on my Triumph Speed Triple and found it to be a pain in the butt. Unscrewing and screwing in was the first step, all the time putting tiny aluminum shavings in the tank as the threads we not perfect. Then you have to have a clean place to put the cap since its not attached. A strong enough wind will toss the cap off of the tank bag
. Then of course you can't lock it up. If I did any touring, especially out side the country, I'd always be concerned someone may have stolen my fuel.