Non Christians can easily come with their Christian buddies to a house concert. And it happened because the focus was on God from the first second. Satan has his sights set on the youth, the leaders of tomorrow. We can so easily fall into the trap of only going for the older people who have money to support us later. But the youth is an investment for the future.
Music has the potential to change their lives for better or for worst.
To not make use of it is to lose that opportunity forever.