Quite simply, the icon means "not on this device, available for download." It appears in such places as the App Store > Updates > Purchased, and iTunes Store > More... > Purchased. And yes, it does appear if you're using iTunes Match.
Since most people's iTunes Store accounts are used on more than one device (computers, your iPhone, spouse's iPad, kids' iPod Touch, etc.), it's quite possible that a song or app has been purchased on another of those devices, but has not been downloaded to the device you're currently using.
As a convenience, the iOS Music app includes songs that are available for download (whether or not you use iTunes Match), not just those present on the device.
To control whether those downloads use cellular data go to Settings > iTunes & App Store. For comprehensive control over how all your apps use cellular data, go to Settings > Cellular.