Juggling has got nothing to do with playing Soccer. I never juggle in a game. The only possible reason I can see for juggling is:
It gets me outdoors and I can do it on my own or with my mates.
It gets me up on my toes.
It helps me to relax and it gives me a skill that I can practice.
It teaches me to keep my eyes on the ball when I strike it.
It shows me how to keep the ball close.
It makes me use my weak foot.
It gets my circulation and adrenalin going.
It improves my concentration so I don’t get distracted.
I can measure and keep a record of my own improvement.
It keeps me fit and helps me keep my weight down.
It’s an easy way to warm up before a game.
I can get hundreds of ball touches in a few minutes.
It’s a good way to stretch all the muscles without straining.
It increases my flexibility and agility.
It teaches me how to read the spin and bounce of the ball.
It gives me more confidence with the high ball in a game.
I can use my head, neck, shoulders, chest, thighs and both feet.
I can reach the intuitive level where I just do it without thinking.
It’s a close repetition drill. It sharpens up my reflexes.
It gives me short term goals that I can aim for and achieve.
I can pick it up and put it down any time I like, anywhere I want.
It improves my balance, coordination, timing and rhythm.
I can make the ball do whatever I want and it makes me feel good.
I can keep it simple or have fun learning new tricks.
I can make as many mistakes as I like without getting shouted at.