But she doesn't do much else.
Irelia on the other hand can do damage, lots of it, while being tanky, and having(unreliable though) light CC. She is a tanky DPS one of the first to be discovered, and still one of the strongest when farm has been gotten.
For tanking pick Leona, if you want a champ you can win with and still take a lot of damage, then Irelia's your girl.
My 23 pence.