Whether it's providing a moment of comic relief in a more serious story or bringing a sheltered character to life, the ignorant voice is one that tends to steal the scene.
Typically an ignorant voice will play for laughs and that is their role in the team or community. They don't tend to offer anything useful storywise but they make sure that the audience is enjoying the ride. In cases where the ignorant voice is used for a character who has lived a sheltered life the transition of that voice to one of more wisdom and experience can be the whole focus of the movie like in Forest Gump for example.
The audience loves the ignorant voice. It generally feels like a fun and relatable character that they would love to have in their crew. The relief of tension often is a welcome breather in a more serious story and the chance for a few laughs helps the audience to have a moment to regroup. But the characters tend to be the ones that will stick in the audience's mind and stories long after the story is done.
There are different ways that the ignorant voice can be done.One way is for the ignorant voice to come across as slower or questioning and so it is often viewed as stupid. It can often be presented as quite confident because the person thinks they know what they are talking about and get words and statements completely muddled up but presented as their truth.