re: Do nets actually work on human beings?

You have to remember as well that Roman gladiatorial bouts were as much about matching styles as matching men. The traditional style vs. style fights were entertaining because they were classic matchups of strength vs. weakness.

Retiarii often fought secutors, and the one of the main characteristics of the secutor was a huge helmet with limited visibility. The retiarius had an advantage when it came to using his net to trip and tangle the secutor.

So it’s not that the net was some sort of awesome weapon. It’s that it was awesome against secutors.