During a recording session multiple "takes" (a recorded performance beginning to end) of a tune are usually recorded. Sometimes the first performance of the tune is so good that the players (and/or producer) feel there is no need for another and that is what one hears on the final product; and, since there is a certain mystique (due to the spontaneity factor) around "first" takes they will sometimes be labeled as such on the LP/CD. However, even in these cases they will record "alternate" takes as backups in case of later technical issues with the "first" or simply a change of opinion about the musical merit of it. These alternate takes are considered good enough for the final product even of they are not used; although they may be included and labeled as such (usually in later compilations).
Recordings (or takes) can get damaged or lost because of the effects of time or human error and viable alternate takes may not exist. What may be left are simply "first" or "second" takes that may or may not have been intended for the final product. The inclusion of a "second" take is more than likely a way to complete the document of that recording session for aficionados who are eager to hear every available bit of the artist's work even if not the very best.
Recordings (or takes) can get damaged or lost because of the effects of time or human error and viable alternate takes may not exist. What may be left are simply "first" or "second" takes that may or may not have been intended for the final product. The inclusion of a "second" take is more than likely a way to complete the document of that recording session for aficionados who are eager to hear every available bit of the artist's work even if not the very best.