The thing is that open world games are more unpredictive. When done right it gives you the feeling of freedom, even tho in some games might be an illusion.
Like for example, in a car chase on GTA you could by mistake go trough a stairs and jump on the train track getting faster to the target car, which will give you a feeling that you gamed the game, until you realize the train is coming you way and you explode.
On a linear game, the train possibility would be either scripted or not exist.
Not only that, on a RPG like witcher, while doing a mission you could find someone that see you killing something you shouldn't and the consequences of that could be that the game breaks or gets harder.
Bugs on open world games, also heightens the feeling of freedom, cause your choice of how to do something could create a script bug, that while may be bad game wise, will heighten the feeling of freedom, since was unpredictive and even broke a script.
So a open world game is all about freedom, and that feeling is so powerful that "goat simulator" bets all its gameplay on this feeling alone.