It's fun
No, Fifth Element has no underlying social message, nor would I say it has any redeeming artistic value.
But it's a riot to watch. I freely admit I have the DVD, tough it was a gift. Honestly, wouldn't have bought it myself.
It's in the rack right next to Starship Troopers, Godzilla, a few Babylon V movies and TV episodes, assorted Star trek discs, John Carpenter's "The Thing" and the complete LOR set.
Among others.
Often I watch a movie just for the entertainment, even when I have to suspend belief and what I know of the Science, ETC used as a plot device.