Potions in Clumsy Ninja are useful, they can help you earn XP which means you can level up faster! With these potions they can help you earning belts! The potions also harvest a big incredible amount of XP!
Potions that give more XP are expensive and needs to be unlocked at a higher level, because it is very rare. The last potion is the Ninja Juice unlocked at level 50, gives 8,000XP, 30 gems to buy and 250,000 coins to buy. The first is the Tornado Potion which doesn't give a lot of XP. The last few are very rare.