Interesting moral implications. Should e.g. child porn still be illegal if no child is harmed? I think most people's natural reaction would be of course it should be illegal, it's child porn!
Obscenity itself requires an average expectation of what obscenity is, otherwise the exception dissipates entirely.
It is therefore easy for me to see that the technological availability of this would change it. there would be attempts by executive branch and legislature that are obliged to simply say something “should” be illegal, and a court wouldnt be able to agree with that on constitutional grounds