[convexfunction]

It's all relative, innit? Compared to "telling people to diet and exercise", which is an almost perfectly ineffective intervention (as usually practiced at least), getting morbidly obese people to become "merely overweight" is huge and results in considerable improvements to life expectancy and morbidity.

As summarized by Wikipedia, "median life-expectancy was 9.3 years longer for obese adults with diabetes who received bariatric surgery as compared to routine (non-surgical) care, whereas the life expectancy gain was 5.1 years longer for obese adults without diabetes", citing this meta-analysis: https://pubmed.ncbi.nlm.nih.gov/33965067/