I'm a big fan of Chuck, too. I've read the book after I've seen the movie a dozen times, at least. I liked it, however, I think the film was more ambitious, bigger, and more complex - even Chuck himself said so at one point.
No, I see your point. Antiheroes ARE fun - especially to watch them, and no, we don't have to relate to them to enjoy a piece of art.
However, when you can identify with a character that makes a bigger impact on you, perhaps. Fictional characters and films touch people like that. Sometimes we are just observers, but it's a lot more enjoyable (mentally and emotionally) when we can relate to these characters. I mean, that's what makes them human and amazing.
I don't necessarily want to be like them or emulate them, but they can make an impact on us. We just need to know how to handle that.
Thank you for reading!