I find edamame a good snack because they are high in protein, moderate in fat, and almost all the carbs in them are dietary fiber. Sugar and starch just make me hungrier for more sugar and starch, while protein and fat tend to assuage hunger longer. But the real key is that while edamame aren't awful tasting, but then they aren't very good tasting either. In contrast, salted cashews are high in fat and protein, too, but it's hard to stop eating them because they are delicious. It's easy to stop eating edamame as soon as you aren't hungry. They don't taste great and they're a chore to grind up with your teeth. So, they are more like anti-hunger bombs than a tasty snack.
And they're cheap — I bought 1.8 pound jars at Costco for $6, although that might have been a special deal. (They are salted, so watch out if that is an issue for you.)
Of course, everybody is different when it comes to diet. If this tip works for 5% of the population, well, that's pretty good.