nash,
Training to failure is designed to activate/fatigue all motor units of a muscle and is typically a strategy employed by lighter weight(60-70%) hypertrophy training.
At heavier weight intensities (85%+) training to failure isn’t needed as all motor units are active and just need to be fatigued.
Both heavy and more moderate rep ranges can be used to build hypertrophy but only heavier weights build maximal strength
–Ralphie