Because BTE hearing aids are larger, they can house larger batteries and sound processors. This means they can provide more powerful sound amplification for people who have more severe levels of hearing loss. They also typically contain more advanced technology and features. This is the main reason why BTE hearing aids are more common, and suitable to people with all levels of hearing loss. However, because of the size and style, the people who most commonly use BTE hearing aids will be those with more severe hearing loss.