Luck elixirs are currently not too helpful in our current end game content Mt Fang, as boss drops do not have a purple, negating the "re-rolled into better loot" into pink loot. Though having a general item re-roll into a pink is rare as well, I think that in end-game content bosses should still have a purple loot table that would somewhat help out with this issue (especially since good drops are much harder now).