I've lost significant amounts of weight (60+ pounds) three times in my adult life, through simple calorie restriction (intermittent fasting, including before I'd ever heard the term). Every time, I've gained the weight back. At the beginning of 2022, I was the heaviest I've ever been.
I've accomplished very hard things in my life, including those that take sustained effort. Sufficient willpower isn't a problem for me in general. I honestly only ever hear "it's easy, just eat less and move more" from people that have never actually been fat. "I did it and I lost 15 pounds, no big deal!" and the like. 15 pounds is easy for me to temporarily lose too. I've done it enough times I should know ;)
I've heard people say that the solution is to eat (healthy food) when you're hungry, and stop when you're full. The thing is, I'm never full. I can eat until I physically can't eat anymore (not something I do regularly, of course), and as soon as my stomach has emptied a bit, I feel fairly hungry again. "Eat until you feel full" is literally a human experience I had never really had.
On this drug, I finally know what people are talking about. I still like food, and I still get hungry. But it doesn't dominate my thoughts. I eat, and don't feel like eating again for hours. I eat something that I'd normally easily eat all of like a big burrito or whatever, and I feel quite full halfway through with no desire to finish. I'm steadily losing weight, with none of the usual preoccupation with hunger, ascetic adherence to a strict calorie plan, etc. But above all, I feel like I must be experiencing what most thin people experience all the time. I'll be perfectly happy to take the drug for the rest of my life, though I do hope affordability improves.
As for side effects: I've had some heartburn, but none of the other commonly reported side effects.