I really think it does help -- hand to eye coordination, that is. The important thing to master is consistant throws. A lot of beginners get to where they can half-way do it but they keep throwing the balls out in front of them. Since you release a ball just before you catch the one coming to your hand, if you're lunging forward to catch the one you threw out too far, that throw is going to have a lot of forward momentum on it, and the whole thing falls apart.
A good way to practice good throws is to do 2 in a circle. You'll want to do it both ways, but start with your right hand throwing a ball in a trajectory that will top out at roughly the top of your head. You want it parallel to your body, and aimed to fall right where your other hand is. When the ball is at the top of its arc, throw the other ball, the one in your left hand, sideways and catch it with your right hand (what else?
).
Many people try to throw both balls at the same time in this exercise. That's useful for future embellishment, but for now, it's better practice throwing them opposite each other in the cycle. Switch hands and do it both ways. This technique can be expanded to 3 in a cirle which is a nifty little trick as well.
To do the standard style, sometimes called the cascade weave, just visualize that each ball is going to be thrown under the one coming to that hand. For best fluidity, you throw when the one coming to the hand is at the top of the cycle. You can buy time in the beginning by waiting until each ball is almost down to the catch hand to throw. This looks more jerky, but you can smooth it out as you get better. The upward motion of the hand throwing will take it right into the one coming down. There's always a ball coming to one side or the other. You've got to get rid of the ball in your hand so you can catch the one coming to it. Pretty easy when you think of it that way.
The fellow in the video starts out with the reverse cascade, in which you throw each ball over the one coming to the hand. It's a bit tougher than the standard, but not too much. Some of the tricks he did are not real tough, but many were. Stringing all that together w/o a single drop is amazing. A bunch of times he came at the ball with his fingers pointing down -- called clawing -- where you sort of snatch the ball. Aim that just a bit wrong and you slap the ball across the room.
I'm telling you -- a little bit of practice every day and you can do it in a couple of weeks or so. Once the urge bites you, you'll have no trouble finding the time to practice.