“An easy method to reduce calories” is fairly revolutionary in the academic diet world. Consistently losing weight is something that people find hard to stick to. A diet that is safe & makes it easy is in and of itself something very interesting.
HN types tend to take the “just eat less, lol” attitude, but in the real world that just doesn’t work very well for the majority of people. There’s no point arguing that people “should” be better at it: they aren’t, for sound biological reasons. Forcing them to behave otherwise & then blaming them when it doesn’t work is simply cruel. Hence the idea that a diet that lets obese people steadily lose weight without any other interventions is a bigger deal than you’d otherwise expect.