Let´s look at an example:
You do 5 reps with 300 lbs on the bench. You rest 5 minutes and do 5 reps with 300 lbs again. Assuming you had a 3-0-3 tempo, you just lifted 3000 lbs in 330 s. That´s 9.1 lbs / s.
Alternatively you could do 8 reps with 250 lbs, take no rest (except for the 10 s it takes for you to set up) do dumbbell bench press for 10 reps of 60 lbs (per arm). Then you, again, take no rest and do 150 lbs for 8. With the same tempo as above, you just lifted 4400 lbs in 176 s, which comes out to 25 lbs / s, almost 3 times as much as the guy above. Now tell me who´s going to grow more muscle.
Muscle is not built from maximal strength, that is mainly a neurological adaptation. Muscle is built by working with relatively heavy weights for long enough to deplete your glycogen stores. Then your body realizes it has to expand your glycogen stores by increasing muscle size.
This type of training is far from “endurance training”, as the weights are heavy and you´re going close to failure on all sets. Your ability to perform after a short break or no break at all will increase rapidly.
You should focus on your workload / time ratio if you want to be muscular and athletic. On diets, this type of training probably burns the most calories.
This stuff goes back as far as Vince Gironda, who called it Density Training.