Buying from the bulk bins is different from buying in bulk. When you buy from the bulk bins, you take only what you need. When you buy in bulk, you often buy much more than you need. And, sometimes, when you buy from the regular grocery store aisles, you buy more than you need, too.
When you buy from the bulk bins, you can save money (and according to this video time, but I’m not sure how the woman who had to scoop everything from the bulk bins with the help of a preschooler got finished more quickly than the gentleman just pulling boxes of the shelves). Natural and organic foods are usually less expensive in the bulk bins than they are prepackaged. You also can save waste because you don’t buy more than you need.
Take a look at this video from the Bulk is Green Council, and see how two shoppers buying the same ingredients, one from the bulk bins and one from the store shelves, fare at the store.