NPR Music’s Bob Boilen uses iTunes Match and has deleted the local copy of his iTunes library.
I’m not sure why people are doing this. When I signed up I decided not to delete anything because the service was still new. I still get mismatches and some album tracks not getting matched from time-to-time. What’s been really great about iTunes Match is having my music with me on my work computer without having to bring an iPod. But at home, my local copy is still taking up space on my drive.
Maybe that’s the point—to free up hard drive space. But I don’t really mind. It’s not hurting anybody.