LocalBitcoins offers a face to face option and your app only make things faster (a little bit) but not secure , people are scared of this kind of transactions as things could go wrong sometimes and you can see stories on the web about them... I personally wouldn't recommend continuing developing this application. Instead , you could start a unique project.
In my opinion , the safest way to trade BTC is when your privacy is not compromised (no ID,Passport required and no one sees your face (the case here) ) .