As I said here, I think recording this information would raise confidence in Beets and allow it to become more lossless. It keeps more options open for beets development in the future. (Imagine taking a second pass at autotagging your library after it received an upgrade that’s better able to understand filenames).
To me the only question is if this should be a plugin or if it should be base functionality. I do welcome feedback if this is a bad idea somehow. What kind of tradeoff must be considered instead of adding fields willy-nilly?