When you match and download files from iCloud Music Library (without having an iTunes Match subscription), however, you get files with DRM; the same kind of files you get when you download files from Apple Music for offline listening.
This means that if you’ve matched your library with Apple Music and iCloud Music Library, you need to keep backups of your original files. If not, you’ll end up with files that you can’t play without an Apple Music subscription.
This is a really confusing aspect of Apple Music. iCloud Music Library has the same 25,000-song restriction as iTunes Match and does pretty much the same thing, so I figured it would behave similarly. Because of this, I thought iTunes Match would be made redundant by iCloud Music Library and be discontinued.
It doesn’t behave the same way, though: iCloud Music Library serves DRM’d versions of your music back to you regardless of where you purchased or ripped it from. But you can still add a $25 per year iTunes Match subscription to your $10 per month Apple Music subscription and get the same DRM-free behaviour. Apple doesn’t explain this very well, and I wasn’t able to test it because my library exceeds the limit (for now). I think that I’ll just be streaming music for now, and not relying upon Apple Music quite yet.
Update: Marco Arment:
I bet iTunes Match gets Google Readered within a year. Don’t get too attached…
This would explain why the details are a little fuzzy. If Match is getting phased out, it might be less confusing when the differences are not fully explained. But for someone who understands the difference, it also feels deceptive, if unintentionally so.