Interesting just in case system. Hybrid of both GPS and BPS for extra accuracy might have benefits. But from [2 - page 13] four transmission towers, accuracy is within 100 m.
Positioning would come once more towers are working together, and based on current data, (again if it is widely deployed) could be down to centimeters.
[1] https://nabpilot.org/broadcast-positioning-system-bps/
[2] https://www.gps.gov/cgsic/meetings/2023/diamond.pdf [pdf]