Some disks I'll upgrade and replace (DSOTM, Talking Heads, Tommy, Ziggy Stardust). Other disks, well, most of them I still only have on vinyl or only on CD. Most of my new hi-rez material is simply new to my collection (although many disks come in multiple formats/ Talking Heads, for instance, come on dual discs, and the CD sides contain several additional tracks each. Donald Fagen, by contrast, included two separate disks, one with DVD-A, and the other being a standard CD.
I think the CD sides of DVD-As aren't necessarily Redbook compliant, though I've never had a problem playing one.