More and more regulated air guns are on the market these days, and some customers are unsure if they need a regulator. More often than not, while having a regulator provides a more consistent shot string than an unregulated model, this is usually at the sacrifice of power and velocity.
In some hunting situations, you may gain accuracy but lose power, which will lessen the possibility of a humane kill. You want to carefully consider if the pellet will have the energy for a humane kill. Many air guns that were designed for hunting are unregulated for this reason.