It can if you waste enough of your time making and maintaining 5 different social/band networking sites for your band, with all of them containing the same group of friends...over, and over...and over.
I don't think it wastes my time. All of our band member's FB profile's are linked with the band's. So any of us can post on that page as the band and edit the profile without having to login a seperate account. It takes about 5 minutes to upload the flier, make and event and invite people, and post on our wall about it.
With Myspace, we just login with the band account, post a bulletin with a pic of the flier, and add a new show which includes all the info, including address. Takes 10 minutes tops.
We'll have to agree to disagree. For my band social networking via the web has been great.