How much data are we talking about?
You also mentioned two concepts. The first was a device paired with a smartphone. The second was a BLE device that simply advertises data, like a beacon, and is picked up by a smartphone.
I would suggest the former, where you actually connect the BLE device to the smartphone. This is the more normal situation and will save the smartphone from having to scan constantly, which can eat up the battery. This would certainly work with bluz with local communication, though you would have to write the app which handles all the low level connection/data retrieval (can use our open source app as a good roadmap)
The advertising approach could work, but you would be much more limited in the amount of data you can send. Also, the phone would have to scan constantly, as I mentioned, and that consumes a lot of power. Finally, the advertisements would be available for anyone to see. Bluz could also handle this, you can change the advertising name to the data you want to send, but it is restricted to 24 bytes.