His "warm up" sets were completely unnecessary he would have made the same results with one set if he had slowed down, reduced the weight a little and really used clean form, more like superslow HIT. Saying he did 3 sets because he did a couple of warmups is daft, it's like thinking your walk to the gym contributes to your leg gains. The RPE on those sets is way too low to be meaningful.
HIT isn't better or worse than high volume, it's more time efficient at the cost of being much more CNS intensive.