When a Nonessential Feature Provides Hidden Benefits
Although they may not play a central role in the function of a part, some features provide optimization benefits if included in the feature set that Creo Simulate studies.
For instance, a round on the edge of a part may have a purely cosmetic function in terms of how the model bears a load. However, if one of your design goals is to reduce the mass of the part, increasing the radius of the edge round would help decrease the total mass.
If you suppress the round, Creo Simulate would be unable to optimize the round's radius. Therefore, despite the fact that the edge round is not crucial to the part's behavior, you would want to keep the edge round as an unsuppressed feature so that you could define a design variable.