Purposefully avoiding academic challenge sounds like a poor strategy for grad school success! From my experience, the best students take classes based on interest rather than ease, and they are more prone to overload their schedules (rather than optimize for high GPA).
The strategy is about optimizing admissions rather than success. Probably because the fear of "not getting passed this important checkpoint" is baked into school. That teaches to optimize for the checkpoints. And people can really take those lessons to heart.
