He hasn't had to use them yet? Are you serious? He was getting destroyed by Nagato and Itachi, was getting dominated by the 3rd Raikage, and is now getting his ass handed to him by Tobi and the jinchuuriki and you think he hasn't needed it yet? Lmao. He hasn't used it yet because he can't(he may be able to later, but he can't right now). Let's see what km and sm do shall we:
Both give the user:
1. increased strength
2. increased speed
3. sensing abilities
4. increased durability
They both give the user the same advantages.