Most audio CD extractors do not provide all of this channel data, as only the digital audio is extracted. When a CD is re-burned, the subchannel data is regenerated, but not a bit-for-bit copy of the original. Sounds the same (usually), but sometimes there is metadata, easter-eggs, and what-not that is omitted. Additionally, some copy protection relied on adding corrupted subchannel data which low end CD players would skip, but high end extractors would not. Having the original subchannel data can be key and necessary to determine whether a sector was infact incorrectly extracted or not.
Most audio CD extractors do not provide all of this channel data, as only the digital audio is extracted. When a CD is re-burned, the subchannel data is regenerated, but not a bit-for-bit copy of the original. Sounds the same (usually), but sometimes there is metadata, easter-eggs, and what-not that is omitted. Additionally, some copy protection relied on adding corrupted subchannel data which low end CD players would skip, but high end extractors would not. Having the original subchannel data can be key and necessary to determine whether a sector was infact incorrectly extracted or not.