Camille is just a better Irelia.
Both are dueling divers with a lot of burst damage, both want to take a single high priority target out and then support their team with further damage.
Well Camille also has much much more gapclosing mobility and escape mechanics on top of that which means that there is not really a point in picking Irelia anymore since Camille does her job better than she does.
And how often have you heard that phrase, especially from pro players? "Champion XY is fine but champion YZ just does his/her job better than him/her."
At this point, new champions that come out often have that problem of filling niches that are already filled by one or more other champions which means that these champions just become discount versions of the new champion.
Please, when introducing a new champion, just ask yourselves: Does the game really need this champion? Sure, Camille is cool and all but she doesn't really add anything to the game that it needed and that it didn't already have.
I mean take Gangplank for example, he added a ton for the game that it needed. It gave poke combs a toplaner, it created a poking fighter with a lot of disengage. He added something the game didn't have before, he filled a niche that wasn't filled before, he just made the game overall more diverse.
And while Camille's character, lore and theme are really awesome, the game just didn't need her, which is a shame if you consider all the effort that was put into her.