Yeah the Chinese Weights were suppose to reduce the racket effect(force) on the tail. As you said it was introduced a very long time ago, back then there wasn't much Strong, Fast, Small servos available, and because of this people were using weak servos that would burn out or die early in the game. Hence the Chinese Weights came along. Now days there's a lot of small,fast, strong servos available so these servos can with stand these forces. The Align weighted grips did drop the force by 10%, but in today's big choices of servos, it's no longer a requirement. Here's a pic of a trex 250 using a HUGE tail servo, to with stand the racket effect.
It's a 500 size mini servo