Of all the silly things that people in politics make a fuss of, one of the silliest is the use of a teleprompter. Somehow not using it when giving talks is considered admirable while using one is seen as a weakness. Some people are more skilled at using it than others and president Obama is particularly adept and yet that very skill has been used against him, as if it is a sign that he cannot think on his feet, whereas he has convincingly proved that he can at unscripted events like interviews and at press conferences.
When giving a long speech, most people use some kind of aid to keep track of what they want to say. Some use written notes while others use a projector with slides. I have heard speakers deliver good hour-long talks without any memory aids whatsoever but these are usually due to them having given the same talk so many times that they pretty much have memorized it and it does not matter if they make a slip or omit something.
But when you are a political figure making a speech on an important issue where words matter and a slip can be highly problematic, it would be silly to not use some sort of aid. I have never had the luxury of being offered a teleprompter when I give a talk but from what I have seen, it is an effective tool that enables the speaker to read while yet maintaining eye contact with the audience.
For the longest time, Donald Trump has been boasting about not using a teleprompter as showing that what he says are his own ideas and not those of others but it has often resulted in him contradicting himself and creating confusion as to what he really meant. But recently, he has used a teleprompter and Stephen Colbert has had a peek at what his screen says.