Will I help business that aren't "Kingdom" or "Christian"? Sure. But what makes me COME ALIVE is when I get to help one of my brothers or sisters in Christ help more of the people that they feel called to.
We all have different gifting, talents, and messages from the Lord. I love when I get to plug in my giftings to help expand theirs. It's like I get to contribute to the breakthrough that their customers get, because I helped them get them. At that point, money becomes a byproduct of the value we both bring.