Yes, calories-wise it's the same, but it's far worse biologically in the US where the sweetener is predominantly high fructose corn syrup. Not all sugars have the same effect.
Fructose has to be ~~porridge~~ processed through the liver and causes much higher incidence of non-fatty liver disease, insulin resistance, uric acid causing gout, etc. leading to higher rates of metabolic syndrome and cardiovascular disease. When someone is ill from these sorts of diseases, they're less likely to exercise or move around, and will tend to want to eat more convenient comfort foods, which only amplifies the obesity issue.
Many of the countries that consume the least amount of fructose per capita are in Europe (Germany, Poland, Greece, Portugal, Finland, etc.)
Yes, I covered that. For example, people who are ill tend to exercise and move less. So calories-out (CO) goes down = people get fatter.
So it's definitely directly relevant.