BLE tech was designed to reduce the power consumption of traditional Bluetooth at the cost of a bit of bandwidth and range. These low power demands use only 1% of the power required by traditional Bluetooth, and these BLE-equipped devices can do broadcast constantly.
Rather than trying to break through the encryption of the data within the signal, the researchers rather concentrated on identifying unique features of the radio signal being broadcast. All wireless transmitters have a signal variance unique to each device. These disruptions are conveyed through the signal and can be isolated from the data, creating a unique point for the broadcasting device.
After digging into it with their own technique, the researchers found that both the false-positive rate and the false-negative rate were below 5%. When researcher tested their technique on Pixel 5, they found the false-negative rate was 0% which means there wasn’t a single case where the fingerprint was incorrectly identified.
By noting these rates, it can be said that this ends up the user's privacy, but there are significant limits on the feasibility of this tracking method. As initially, not all imperfections are unique, some BLE chipsets produce similar imperfections, making identification much more challenging. Furthermore, these fingerprints can vary based on temperature, which limits the Bluetooth vulnerability to more stable environments.
As almost all our devices from wireless mouse and keyboards to our smartwatches and speakers come with Bluetooth connectivity. We don't even bother about the security of Bluetooth or its encryptions, but for your privacy concerns, it would be to turn off your Bluetooth, at least when you don’t need it because Precaution is Better than Cure.