Used my Injinji's for racquetball this morning. They really help out with all the sudden transitions on my poor toes.
Everybody's feet are different. If you read "How to Fix Your Feet" you see that the author gives multiple cases, causes and solutions. There is no one size fits all solution when it comes to feet.
That said, Injinji's are the best solution I have found yet. Every time I buy a new pair of hiking boots/shoes, I give it a go without the toesocks and invariably return back to the Injinji's. They help me go blister free on my short and long hiking trips, which is something that I never was able to do before I started using them.
So, as others have said, if you find you are prone to getting blisters between your toes, Injinji's may be a good solution for you. Hydropel or other foot lube may be a viable solution. Also, as others have said, if you don't have footwear that is sufficiently wide enough in the footbox, that could be part of your problem as well.