iCloud status "Apple Music" means that Apple already had that same song and recongnized it.
So if you play the song from another device (iPhone), it plays that song which was already in the cloud without the need to upload your song from your personal, local, iTunes database.
But make sure you do not delete the file on your harddisk, because then you ONLY have Apple's version in the cloud, which you cannot access anymore after your subscription ends.
You can check what songs are only in the cloud by looking at the "location" attribute.
If it points to a real file (.mp3/aac/etc) it's local on your disk.
If it is "icloud" the file is only in the cloud .
If it indicates only a subfolder "Apple Music" in your iTunes folder, then it's an iCloud song which made available locally. (Downloaded, but with DRM, not usable after subsription ends)