This glitch has no uses. It is just cool IMO because KH2 in general doesn't have many glitches.
If you switch Genie forms while in a Reaction Command that freezes time your party members will not return after Genie is gone. This works on Demyx's Reaction Command. So if you REALLY hate your party members, you can do this. While you are alone with your party member stuck in a endless abyss somewhere, you can't use drives, limits, switch party members or another summon. It is just stuck saying ''Dismiss" on the command menu.
This also works on the Gambler Nobodys Dice RC game. Just incase you are wondering, in Port Royal, you can't switch party members in the menu after you kill all the enemies alone. Switching their weapons, messing with their abilities, anything you can think of, you can't bring your party members back unless you leave the room or die.
This will most likely work on 2.5 if you care to try yourself. Sorry if it is a bad explanation I am not good at explaining things at all.