shaco ult has more uses than just "make your enemy guess the real version of you"
1. it gives AD shaco huge damage incrase when attacking with both the real shaco and the clone
2. you can use it to juke spells (use ult right before a spell is about to hit you, and the spell will fizzle out and hit nothing)
3. use clone to body block skill shots
4. use clone to face check bushes when you know their team is waiting there, for example, when both teams are trying to bait a baron fight
5. use clone to tank towers