This allows more flexibility, and is very similar in the non-effective case, since whenever a supermartingale d is given, there is a modified function d which wins at least as much money as d and which is actually a martingale.
The concept enables greater adaptability and shares similarities with the non-effective scenario. When a supermartingale d is presented, it's possible to create a modified version d that wins at least as much money as d and functions similarly to a martingale in certain contexts.