I get your point but I think that would just make it harder to get traction/attention , and the success of the app/web would proportional to the number of people using only app.
I'm trying to achieve something simple and easy to use. Using a app just for the geo-location option would not be enough IMO, it would have to bring something more to the table.
Not location data from your own app.
You can literally buy aggregated location data from 3rd parties. In some cases, even directly from the carriers themselves.
The infrastructure is already there. All you have to do is be a middleman.
Then once you get enough people using your own app, you can further reduce costs by not having to buy the data.