The service built its reputation on catering to those who enjoy listening to bleeding edge music like demos, remixes and bootlegs. Ideally, Next Wave exposes SoundCloud users to that kind of music and encourages them to come back for more. If you have a goth rap epiphany, you may be more likely to stream every bit of it that you can find... and SoundCloud will be ready and waiting.
The problem: is this the best use of SoundCloud's limited resources? That's not so clear. Underground scenes by their nature only cater to a small group, and there's no guarantee that they'll be big enough to make a dent in SoundCloud's bottom line. And it's not as if SoundCloud will stand out from the crowd when Apple and Spotify are producing their own video shows. Still, the potential gains are obvious. It's just a matter of whether or not they'll be enough to make a difference.