The themes in the written version of the play are subject to the interpretation of the readers. In a live performance, the themes are explored and presented in a more concrete, clearer and specific version. The universal theme found in the written version is interpreted based on the minds of the directors and writers.
The most obvious answer to the question of "how a live performance of The Crucible would change the impact or presentation of the themes in the written version" would be that when something is read, the themes are subject to the readers' interpretation. On the flip side, movies, plays, etc. more clearly present the themes of the story. However, the themes or morals of the story in productions based on it are usually based slightly less on the author's original intent and more on the stage director's interpretation of the story. Another thing that is a significant difference between the written version and whatever live production that is made is that in the written version, the author can articulate the thoughts of their characters. In contrast, in live performances, doing so requires a narrator, creating some dialogue to incorporate it, or simply leaving it out.
Since it is an attempt to undermine the argument of an opponent, writers and speakers use it to belittle or weaken the opponent's position, to make it vulnerable to an argumentative attack.