I would have thought that a mobile telco could generate this data already just from what they need to route data (and voice calls) to each phone, at least to a somewhat coarse level, without needing to have apps upload this.
They were after data for other carriers and/or more enriched data than they could easily collect. They could use this data for their own marketing and/or network planning. e.g. “We have the least share in market M where some significant proportion of all cellular users , based on twitter data, love NASCAR and spend relatively a lot of time on their phones at racetracks and Walmart. Lets increase capex around race tracks, do a promo with NASCAR and Walmart, and buy some appropriate ads.”
