Magic is something used to accomplish your will. It's a technology, of sorts, which you manipulate. Harry Potter goes to Hogwarts with the intent to learn how to use magic. Kvothe, in The Kingkiller Chronicles, goes to The University to do basically the same.
Magic is something you use. God is someone you trust.
If your Christianity is utilitarian, then you what you have is magic, not God. The Bible is not for helping you get ahead in life, the Holy Spirit is not a genie. Magic is about you, Christianity is about Christ.
This magical faith presents itself in many forms. Our prayers are focused on what we want or need. And we only go to our Bibles when we are in a crisis, have a question, or want to feel better about ourselves.
These things are not tools to be wielded for our comfort or worldly gain, but for submitting ourselves to Christ.
Our faith is not magic, but a relationship with a person. One who is loving and wise. Who not only knows what's best for us, but wants to do it just the same.
This is why I'm thankful for this difference. God knows far better than I do, so I'm glad he's the one with the power.
I can't manipulate him. And that's a good thing.