The main advantage here seems to be that it is highly targeted based on location. It can both catch tourists and and avoid bothering people who are out of town.

The downside is that people are more familiar with alternate communication methods with SMS or EMail where people can check their history, forward to people who need it.

Furthermore (like SMS) this requires a connection to the cell tower, which some tablets may not have even if they have internet.

But overall it seems like a good idea.