I thought the "balance" was and continues to be that Vorbis delivers at least as good a quality as AAC at equivalent bitrates, if not better, better quality tha

I thought the "balance" was and continues to be that Vorbis delivers at least as good a quality as AAC at equivalent bitrates, if not better, better quality than MP3 at equivalent bitrates, and is FOSS which way tips the scale in its favor. I haven't seen and continue to not see any reason to MP3/MP4 in the manner you describe. (And if Vorbis isn't on par w/ MP4, my impression is that it is certainly good enough at decent bitrates that it wouldn't matter.)