Why use an alternative profile with the Monte Carlo report? Using an alternative profile is a way to compare a plan with data changes to your base plan. For example, we might wonder if purchasing a vacation home (or selling a vacation home) puts our plan at more risk or makes it less risky. How does retiring early impact the risk profile of our model? What about taking RMDs for the first fifteen years instead of starting smooth withdrawals at age 65? Any such change might have some impact on the risk profile of our model. Creating an Alternative Profile and comparing it to the base profile using the same investment strategy in both is a good way to isolate the risk impact of that change in our plan.
Another reason to use an alternative profile is to change the safe return rates which functions as a change in spending behavior. Using a more cautious return rate will tip your trajectories upward, in effecting hedging your bet regarding return rate risk or sequence of return risk.
MaxiFi does allow you to also change the investment strategy in the Alternative Profile, and that is an option as well, but the Alternative Profile gives you an opportunity to compare the risk impact of differences between two plans that are not related to investment strategies.