The answer is simple: because it will not be beautiful if the right clothes will not be prepared in advance.
Location, light, decorations could be perfect. However, if your style doesn’t match with the surrounding area, if there are irrelevant prints on the clothes and so on, the magic of photos will disappear.
Just imagine if, for example, this boy wears jeans and T-shirt with dinosaurs, will you like this picture? 😉
I don’t say that the only way to create beautiful photos is using special costumes. It could be usual clothes as well but the style and color of the outfits and shoes is one of the most important things. Don’t be lazy and spend some time for preparation. You will be satisfied with the result more than ever, and I’m always ready to help!)