"Veggie burger that tastes better" is kind of a big deal, because (to at least a first approximation) the only reason people don't exclusively eat veggie burgers is that they don't taste better.
I believe the parent meant these taste better than a regular veggie burger and not a beef burger.
People also eat meat because it's a lot more energy efficient. One real burger lasts me for 7+ hrs where a veggie burger maybe 2.
Could just be the veggie burger has less fat. Fat/oil keeps you satiated. But it's always easier to add more oil to a veggie burger, than it is to make a meat burger lean.
I thought protein was better for satiation than fat?
Fat is more satiating per gram, but protein is more satiating per calorie.