It's an alright item, but Frozen heart is better on him. It has more cdr for more siphoning strike spam(actually higher damage output given decent farm), and lower cooldowns on wither makes it easier to lock them down(probably more so than IBG). The aura also is really good and it overall grants more stats.

Iceborn gauntlet isn't "useless" as an item, it's single handedly the reason Ezreal is so good right now.