In the world as we know it, anyone can take an outstanding picture on their smart phones and tablets and they're great! They especially look great with the more advanced displays, such as retina display. You can hire an "average" photographer who lives by "natural light," which is good under certain circumstances, but in the pro world, we view those natural light - only photographers as those who are afraid to learn about lighting. They learned some auto skills and were not really trained and yet they charge as if they have full command. They take the same picture you could with their camera. The trick is in knowing when and how to use the proper tools. That takes training and application, not a mere investment in a camera and a couple of how to books. YOU can take a snap shot so why pay someone else to do that. The average guys will bump up the exposure, so you have a higher key image, but you have to know that it's over exposed.
A photographer can retouch and give you a dreamy image of yourself. Isn't that why you hire someone? To make you look good? The following example shows a retouch and in it you may notice a slight variation in her eyes only because they were opened up with light! Her skin is creamier and there is more light on her.
Let's face it, when you look in the mirror, or let's say when this young lady looks in the mirror, don't you think she sees the girl on the right, not the girl on the left. Cameras shoot for medium gray and it produces a haze and darkness and that's not who she really is. You look better than the light you might have shot in the bathroom mirror.