Why do first-person shots in movies always bring fear to the audience?

The first-person perspective has a strong sense of substitution. Fear or other feelings are the tone of the movie itself. It can only be said that thriller/horror films are more likely to use the first-person perspective. I think this fear is caused by the uncertainty and sense of loss of control caused by the sense of substitution. Relatively speaking, since the bystander's perspective gives the audience a hint that it has nothing to do with it, it will not produce such a strong sense of involvement.