PandaPacha
My guess is that Apple is gathering all those data in order to build their own Skyhook. It makes sense, specially when you keep in mind that Apple bough the mapping company Poly9.
Apple acknowledged that to the House of Representatives. They're gathering data about their customers, including GPS : [PDF] http://markey.house.gov/docs/applemarkeybarton7-12-10.pdf
II / C / 1 / a. : "Second, to help Apple update and maintain its database with known location information, Apple may also collect and transmit Cell Tower and Wi-Fi Access Point Information automatically. With one exception, Apple automatically collects this information only if the device’s location-based service capabilities are toggled to “On” and the customer uses an application requiring location-based infomiation. If both conditions are met, the device intermittently and anonymously collects Cell Tower and Wi-Fi Access Point Information from the cell towers and Wi-Fi access points that it can “see”, along with the device’s GPS coordinates, if available. This information is batched and then encrypted and transmitted to Apple over a Wi-Fi Internet connection every twelve hours (or later if the device does not have Wi-Fi Intemet access at that time)."