If I open your silverware drawer, I expect to find the forks in one place, the knives in another, and the spoons in another. I expect it to be organized. If I open your silverware drawer and find that the forks, knives, and spoons have been dumped into one place all together, it will take me longer to find what I need and set the table. Likewise, on your e-commerce website, if you have dumped all of your digital cameras onto one page and don’t allow me to search by brand, or price, or features, then it’s going to take me longer to find the camera that I want. If it takes too long, I might just go to another site.
In addition to separating things like forks, knives, and spoons, users expect a certain hierarchy. If I’m at a friend’s house looking for some ice, then I will go to the kitchen, open the freezer half of the refrigerator, and look for the tray of ice cubes. In my mind, I do something like this when I’m looking for ice cubes: kitchen > refrigerator > freezer half > ice cube tray. It’s important to respect natural hierarchies when organizing information and products. If my friend temporarily moved his ice cubes to inside the oven or under the bathroom sink, then I would have a hard time finding them.