Very good job. Thank you !
In fact two marginal uses for indexes zero were pointed out.
The first one was found by Infrared Archer in
http://www.hydrogenaudio.org/index.p...ST&f=20&t=1642 : in a hardware CD player, when you program a playback with a different track order than the natural one, the gaps are left out in the playback, as the player jumps from track to track.
You mentionned the other one : if someone, for a given reason, wants to get rid of the original gaps on purpose, it will be possible from the copy only if indexes zero were copied with a cuesheet from the original CD.