Avengers: Infinity War and End Game question

Question

At the end of Avengers: Infinity War Thanos snapped his fingers and that erased half of the life in the universe etc. But to my understanding there is no rule book with the gauntlet. He snapped his fingers because that's how he decided to channel his intentions, he mentioned at one point that with all 6 stones he could simply snap his fingers and half would cease to exist (paraphrased badly).

So why did both the Hulk and Iron Man need to do the same in Avengers: Endgame?

Almost as if snapping fingers was the only way to achieve this particular task.

Answer 1

So why did both the Hulk and Iron Man need to do the same.

They didn't.

The "snap" is a visual interpretation of the will of the person doing the "snapping".

It's there for the audiences benefit so that we have something to attach to the significance of the action.

Almost as if clicking fingers was the only way to achieve this particular task.

Clearly, that's not the case since Thanos' original snap and the Hulks are direct opposites and Tony's is different to Thanos' universal snap.