Another option is to look at the other side of the coin:
He now has a spare ball that can double as dry lane ball, maybe reducing the number of balls he needs to carry. He can now also throw that spare ball at spares he might not have been able to in the past, like double wood spares, since he now has some drive at the pin deck. He can now also, potentially, be more aggressive when trying to convert splits because he has a ball he can now get to "turn" at the end of the pattern. All this for just making a small adjustment in how he shoots his 10 pins.
I was "lucky", my first plastic ball was the Ebonite Clear Wolf, so it had a real weight block in it. So I learned how to shoot 10 pins that way. I wouldn't trade it for the world...I could never throw a plastic ball with just the pancake weight block. This ball is the best dry lane ball I ever had, and I will shoot 300 with it one day, lol.