It is More Street English (or the target language)
Since reality TV features regular people, they will use more street words and sentences. This can mean it is more conversation and or have more slang. This will give you a sense of what a real conversation on the street would be like.
In movies and drama shows, the conversations are scripted and, often, predictable. They might even use higher level vocab that normal native speakers do not use.
For example, someone in a clothing store in a movie might say “I am browsing.” But regular people would just say “I’m looking.” Both are correct, but one is higher level… and not so used on the street.
Language learners often say that it is actually easier to follow reality TV due to the “street level” vocab.
It Shows Cultural Norms
When you see the people interacting, it is not dictated by a director (though there might be some encouragement of where to take the conversation). They are behaving how they normally would in real life. This means: shaking hands, hugging, or not touching at all.
This can also be with how they greet each other. For example:
“Hey man” vs “Hello, how are you?”
Both could be used in the street, but when? Does Tom Cruise in Mission Impossible show an actual representation of how people greet each other?
It Isn’t SO Scripted
As mentioned, there are some scripted moments or moments where the producers poke the individuals to get a specific conversation or outcome, but for the most part, these people are doing what they think it is best or fits the situation.
In interviews after the show, the people often talk about how those feelings and actions are pretty genuine. You should keep in mind that today’s society is all about social media. They can ruin their whole lives/careers with anything said or done on the show. So, they aren’t going to do anything on purpose because a producer told them to.
This is clearly seen in “Love is Blind.” I talk about the show in the next section, but in season 3, one lady seems to attack one of the men and now, the internet believes she is the villain and she gets a lot of hate. I doubt that was her intention.