The big advantage comes from its packaging and everything built into the chip. It comes in a 144 pin lqfp package, which means that routing pins can be done by a couple people with real minimal amounts of training, and it can be laid out onto a two-layer board, which tends to be a lot cheaper than a four layer board which a bga package pretty much requires. It's also got a dac and adc built in which has the circuitry to directly drive headphones, so you don't need amplification circuitry to do that. Similarly, it's got integrated power regulation, so you don't need those chips either. Finally, all the info on it is available in a datasheet you don't need to jump through hoops to read [1]. It's not as fast as a chip, but because of everything it has, it's much more flexible for when you are designing something.

[1] http://www.nxp.com/assets/documents/data/en/reference-manual...