Just because you never used a feature such as virtual copies isn't much of an argument. Do you never use LR's History steps? Not in xmp. Flags? Not in xmp. Collections, stacking, etc. You know what I'm going to say.... they're not in xmp either. ...
As I mentioned in my previous post, ideally, everything would be written to XMP.
The fact remains that a RAW converter is just that: convert the RAW files, based on your adjustments, to JPEG. The bare minimum, all these adjustments should have the option to be written to the XMP. This option CURRENTLY exists when working with sessions so it's not some crazy expectation. Not only that, you can export your adjustments to XMP via the file menu which is not practical to do after each individual image. So, the capability is there, just make it automatic via the preferences like in sessions (well, the preference is there but it doesn't do it when using catalogs).