Indiepedia exists because Wikipedia does not deem many bands 'notable' enough.
There is currently no place on Wikipedia for many upcoming bands, local scenes, or lost and almost forgotten bands from years past.
We want to collect that information and make it readily available. If that could be done on Wikipedia, that would be great. Untill that time: Indiepedia.
I agree, many of the articles indiemedia.org seems to want should be in Wikipedia.
But Wikipedia has become very picky lately and has begun rejecting new band articles. I recently tried to add Australian band Pre_Shrunk. They're been signed, have released three albums and four EPs and have had multiple ARIA nominations and have toured constantly for years. And yet they were rejected as an "insignificant" band.
So even though I think anything and everything should be in Wikipedia, until they get overthemselves a bit and remember why they became as popular as they are (by allowing anyone to create an article on anything), indiemedia looks like it'll fill that hole.