First of all nobody said that 1 rest pause set leads to more growth stimulated than 3 regular sets to failure.
ONE rest-pause set will lead to more growth stimulation than ONE regular set to failure because you are creating more muscle fiber fatigue with that one set.
But if you are creating more muscle fiber fatigue with 3 sets to failure than with 1 rest-pause set, you will probably stimulate more growth with the 3 sets, provided that the overall volume is not too high for you.
The one thing I will say that MIGHT advantage the rest-pause set over the 3 sets is that you might fatigue MORE muscle fibers. Why? because you don’t give the working fibers the chance to recover.
In a rest-pause set when you hit failure a first time, then rest a few seconds to give the CNS a short break (and also replenish a small amount of ATP to fuel muscle contractions) the fibers themselves don’t have time to recover. So when you resume the rest-pause set you can get more reps in (because of CNS rest, clearing some metabolites and restoring ATP a bit) BUT you have to use a lot of new fibers to do the job because the fibers fatigued in the first part of the set didn’t have time to recover.
If you do 3 regular sets with enough rest between sets, many of the muscle fibers than were fatigued in the previous set have time to recover. As such you will not need to use as many “new” fibers in he next set.
The result is that you might fatigue more fibers with rest-pause BUT fatigue fewer fibers to a greater degree with straight sets… both have their advantage so both have their place.