This may already be known, but in case it isn't, Cancelling not only removes all buffs your characters get from Barrier, Deban, Saner, Shift, Vision, etc., but it ALSO removes any elemental defense benefits you would get from items like the Plasma Field. This did happen in Bich's 2nd place run but I don't know if anybody noticed, but after hunting in the Phantasy Star Cave, somebody did notice this (though he hacked a lot of the game). I can confirm that this does happen in vanilla PSIV as well.

It shouldn't change the strategy at all since Kyra will still get Reflect Shield and Plasma Field, but it is something worth noting.