Is the area properly mapped in OpenStreetMap? Organic Maps uses OpenStreetMap data, if addresses are not present there, then it's up to the users to add them.

For the UK, it doesn't have house names/numbers, but streets + towns work fine.

Not in the US.

I'd be careful of making sweeping statements about 3.7m square miles of land from your doorstep in LA.

I'm in the US too, and here in Atlanta I use Organic Maps frequently to find specific street addresses. It works quite well. I would agree with the other responses here suggesting that maybe you could contribute some data to OSM for the areas you encounter that are missing street numbers. You'll be helping yourself and others!