Churches need to have resources to survive
Just like the rest of us, churches need a place to shop. Obviously churches don’t have legs to go shopping - they aren’t even alive. So the actual church doesn’t do the shopping, but the people in charge of obtaining things for the church do. Their responsibility is a heavy one, for they could be looked down upon if they get things that the congregation doesn’t like.
Luckily these purchasers have a place to go that knows what kind of things to sell them. They can supply them with more than enough high quality church stuff to keep the congregation happy for a long time.