Whether to use BLE or UWB for your indoor positioning project will depend on a number of factors. The main considerations are budget, positioning accuracy, latency requirements, and the ability to provide/attach a UWB tag to the tracked object, compared with using a mobile device as the tracked object.
The short answer is that UWB requires more infrastructure, costs more and provides a much higher level of positioning accuracy. It is important to weigh the benefits of each and you can learn more about the differences here.