First of all, apologies, I didn't mean that the business card would get me booked, I wanted to mean that it could help me get them by showing a high quality product associated to my brand (apart from the photographs, of course?
I see all your points here and I understand them. I do have a nice business card in paper, but I wanted to do something special for those customers that you really feel "good" about. That you want to show them that you care about quality. Of course I agree with you that the main thing that will get you bookings is your work, but something extra, something unusual, helps catching an eye. I have always loved a good business card.
My primary objective would be for wedding clients, people I have the initial meeting with about their wedding, and that I feel that the card would help nudge them towards me. I am starting in the business, so anything that could bring them closer to me helps.