Like Axxe said; it can turn an ordinary photo into a great one. Since most people use digital cameras of some sort today, and film isn't involved; you can edit images to look like they were shot using film. Different film has different looks to it once developed. Shooting expired film for instance; has a fairly large following since it has a different tint, and other attributes compared to new film. You can achieve this look using post processing programs like Photoshop, with out shooting with film.
Like this shot, which I tired to make as vintage as possible without Photoshop. I used Picasa for this one instead.