The sound quality from the speaker is decent, much better than a lot of more expensive devices (though I’d still prefer a Jambox for audio fidelity), and it can actually go quite loud. Not room-filling or anything, but plenty loud for private listening. But the main advantages are the fact that it acts as a very good Bluetooth speakerphone, charges via micro USB (and can be charged with your external Z10 charger), can go weeks without a charge and has a 3.5mm headset jack, which essentially makes it a Bluetooth receiver for use with a stereo or headphones.
The hardware accessory market is a place where it’s hard to compete with platforms like iOS and Android, and that’s likely why BlackBerry is taking an early interest in doing things itself. And they’re off to a good start in that regard, if my experience with this speaker is any indication.