They don't solve any problems while creating 2:
1) They will develop slack or "play" in them.
2) They will take a very long time to change when it's time to change cogs during training/racing, which happens fairly often. A racer could change cogs up to 4 times a session (16t for warmup, 14 and 13t for racing, 16t for cool-down).
So, why bother? If the current system aint' broke, don't fix it.