No, not at all, you can absolutely use vanilla extract. Vanilla pods are expensive however, they can be used more than once! When you have removed the pod from the cream, wash it gently with warm water, then allow to dry on a paper towel. When dry, you can cut it up and add to a jar of sugar to make vanilla sugar, or add it to a small bottle of vodka or rum. Over time the vanilla will infuse the alcohol and you will have home made vanilla extract. Keep adding vanilla pods as you use them for a stronger vanilla flavour.