Well, I can tell you how I designed/intended them to be used...
1. Riffs that make you go "hey, I could write a song around that!" - so you do.
2. For people who don't play guitar, but need a guitar riff...like audio for video soundtracks or beds.
3. To drop into dance mixes as cool variations. They all stretch very well to the trance/dance range. Most can also stretch down into the hip-hop zone.
Have you checked out the
audio demo?