Why Hire a Photographer?
Photography both documents and expresses the work that you do.
You need to document your work so that you can show people what you can do by showing what you've done before.
But you also need to express that work. Yeah, that sounds pretentious, but here is what I mean.
A camera isn't a human, a camera just records reflected light for a fraction of a second. A professional architectural photograph does much more--it communicates some of the feeling you would have if you were inside the room or in front of the building.
By artfully framing and lighting the shapes, textures and colors that make up a space, a photographer tries to share both what the designer intended and what you would experience if you weren't looking at pixels on the screen or page, but were actually there, inside the room or in front of the building.
But why hire a photographer to take the pictures? Can't I do it myself with my own camera?
Hire a photographer for the same reason you would expect your clients to hire you. Your clients could buy some CAD software get some sample books and start trying to do what you do, but most wouldn't succeed as well as you because you've dedicated a great deal of your life to what you do. You're good at what you do; the skills and thought processes that are second nature to you would be fumbled over by a novice.
That said, photography isn't rocket science. It isn't a domain of knowledge totally alien to designers and architects. You are visually motivated people; you visualize both volumetrically and graphically.
And that is why I chose to work in this field, I consider myself a collaborator. You make beautiful work that uses space, and reflects light in wonderful ways. I'm there to use my particular skills to collaborate with you, to turn your beautiful spaces into clear, clean expressive images--ideally, so that potential clients will see them and hire you to make even more beautiful spaces in the future.