It definitely sounds and works better via your computer mic and speakers than over your smartphone. At least it has in my experience.I have never needed or wanted to do this. I always have my smartphone right next to me. What's the advantage? I guess I can see it for text messages.
For text messages the real advantage is you get to type out long ass text messages on your keyboard and it does not interrupt your work flow because it is just another window on your computer instead of picking up your phone and responding to the same. Definitely the most first world of first world problems. But I love it.