Recently, as I handed my business card to a friend I'd just made, he looked at it longingly before putting it away, and commenting, “That’s when I’ll know I’ve really made it.”
And it’s true, having your own business card comes with a certain cachet — that you’re an adult, that you’ve “made it” in whatever profession you’re trying to “make it” in. It says you're serious about what you're doing, and demands you be taken seriously.