Is it really an eye opener? Just because data isn't directly used it is not safe to assume that data is discarded.
The cell companies need data on crowd movements[1] to best allocate network resources, to provide a better service. This collective data has to come from a collection of individual datum. Data might need to be collected for all users over a long time frame (years) to correctly identify (for example) how much additional infrastructure is needed near stadiums in football season, how the profile of commuters is changing and what new suburbs are being inhabited.
If we want a stable and reliable cell network, we have to allow the cell companies best plan for our usage.