With all the rapid developments in improving assistive listening technology, there can be some confusion about the meaning of "wireless" hearing aids, "digital" hearing aids, and "bluetooth" hearing aids. While these terms are somewhat interchangeable, there are some specific differences.
Hearing aid manufacturers are using the wireless capabilities of hearing aids to take advantage of Bluetooth technology by utilizing the digital streaming capabilities of existing bluetooth enabled devices, and enabling these devices to link to wireless (digital) hearing aids. To be clear, the hearing aids themselves don't use bluetooth. Rather, the "streaming technology" in the hearing aids takes advantage of surrounding nearby devices which are utilizing bluetooth technology by providing a secure, direct data link between the wireless receiver in the hearing aid and any bluetooth enabled device. Devices are linked one at a time.
This can enable those with digital hearing aids to link to their cell phones, iPhone, iPad, and any other bluetooth capable device such as a television or a computer. In the same way your computer can connect to a wireless bluetooth speaker, a computer or television can be connected to the hearing aid of someone with hearing loss within 30 or so feet, enabling comfortable listening via digital reception directly into the CI or hearing aid of the user.
To learn more, here's a great article on the integration of bluetooth technology into assistive listening devices.