How does the weight watchers diet work?

I'm a female and 19 years old I went on the weight watchers diet before, if you're serious about losing weight I would suggest weight watchers isnt the way to go about it. It's confusing, it's all about points nothing to do with calories, and it's easily just a money making scheme, to be part of a weight watchers diet, you have to buy the materials, even if you dont want to pay to join, the food is really expensive and very little amounts-you need to buy calculators and grids to work out the points and its all really fussy. I gave up on the weight watchers diet as it wasd far too leniant and i was eating far too much a day just because i felt it was okay to eat their nice foods as it was 'healthy and slimming' i went on my own diet plan and lost 2 and a half stone in just under a month, and have not put any of the weight back on since. The weight watchers plan does not work, and it's clearly just a scam to take peoples money.