What is the purpose of presenting a false dilemma in a speech?

convince the audience that there are limited options.  

Explanation:

The false dilemma is meant to present a limited number of alternatives - most often spoken as if there were only two - when in fact there is more. This fallacy is linked to a limited and simplistic view, which does not take into account the multiple variables and contexts involved in a situation.

Fallacies such as the false dilemma can be used on purpose to manipulate opinions, but it is much more common that they occur by accident, without this bad faith: none of us are free to commit this kind of error, either by lack of attention, lack of knowledge or lack of time to think better about what we are saying.

an argumentative essay presents objectively a topic and its main characteristics. besides, it states all this information and facts by giving authentic and substantiated proof to the audience. by contrast, a persuasive text purpose is to convince the audience about some facts by presenting them according to his/her emotions and feelings. the main purpose of a persuasive text is to convince the audience to agree with the author´s opinion. on the other hand, in the argumentative essay, the author leads the writer to recognize his/her point of view as the correct one.