Excess calories make you fat regardless if its sugar or fat. Try drinking those American super size cokes servings from mcdonalds and you will get fat on a low fat diet. My argument is 1 calorie of fat is better than 1 calorie of sugar*
*for most people. All humans differ slightly, some people can eat 3000-4000 calories a day without putting on fat because they have a very fast metabolism.
So the question really is does sugar make you crave more sugar (in calories) or does fat make you crave more fat(in calories)?
I would argue that its the sugar content that makes your crave chocolate. Try eating some high fat dark chocolate (80%)... Dairy milk/mars etc is more sugar than fat so that example is not good!
Again biscuits contain a lot of sugar. e.g Look at hobnobs. More sugar than fat which I argue contributes to the cravings, I don't think anyone would crave a hobnob without sugar, it wouldn't taste very good!
Most of your examples are high sugar as well as high fat, so they are not good IMO. I agree high fat AND high sugar is not good.
The argument for fat is that fat satiates. It takes a longer time to digest, keeping you fuller for longer and not feeling hungry. I know when I have a high fat lunch I don't need to eat anything for 4+ hours, otherwise I have to eat something within 2-3 hours. (But I exercise quite a lot so I eat frequently anyway).
Remember excess sugar gets converted to fat anyway. Look on google.
Humans have not evolved eating highly refined sugars, it is only something that has been done in the past few centuries. We can eat no sugar (other than what is in fruit) and have a completely healthy and balanced diet. It is not something that the body needs.
Being fat does increase the risk factor for diabetes, but if I eat a lot of fat and I am quite lean, my risk of diabetes is low. The same is not true if I eat a lot of sugar. Sugar increases insulin resistance.