A large number of people use their hierarchal playlists to reproduce something almost identical to soup views - i.e. Artist / Album / Tracks and variants thereof.

I use hierarchal playlists in many ways other than artist/album.

Here's an example:

I have two playlists, one called "(Low key)" and one called "(Road Trip)". I've found that "Low Key" is always a subset of "Road Trip", because I like having low key songs intermixed with high-energy drivin' songs. So it's best for me to just have a link to Low Key inside the Road Trip playlist so I don't need to update two separate playlists when I add a tune to Low Key.

It also comes in handy with regard to the "Ignore as Child" flag... I can ignore my "(Car Talk)" playlist so the episodes don't come up in shuffle. I don't have to individually tag or hide the episode subfolders, I just drop them in and hit Synch.

I'm currently in a quandary, because I want to fully synch my Rio Central with my Empeg, making them identical. But the Central doesn't have hierarchal playlists or Ignore As Child, so I will lose many of the features I've come to depend upon on the empeg car.