That's a silly statement. If it didn't break suspension of disbelief then it's because you didn't even realize it was CG! If you go to movies at all then I can all but guarantee you there are CG shots that you had no idea were CG.
Here's some super impressive CG from the first Captain America movie back in 2011. Crazy insane stuff they're doing it. And that's for a very, very extreme case. You better believe they are doing slick stuff in non-extreme cases!
http://www.fxguide.com/featured/case-study-how-to-make-a-cap...
For Iron Man it's not quite the same because it's a suit but it's just as impressive. Since Iron Man 2 there is no full suit worn by an actor. There are no legs and at this point there are barely even arms. There's a chest piece and open mask face piece and that's about it. http://movies.stackexchange.com/questions/2198/how-are-the-i...
In The Social Network there are a lot of scenes with the Winklevoss twins. Spoiler: They didn't use twin actors. They used two actors and CG'd the face of one onto the other body. No way in hell did you call this out on first viewing. (number 3) http://www.totalfilm.com/features/50-cgi-scenes-you-didn-t-n...
Here's some super impressive CG from the first Captain America movie back in 2011. Crazy insane stuff they're doing it. And that's for a very, very extreme case. You better believe they are doing slick stuff in non-extreme cases! http://www.fxguide.com/featured/case-study-how-to-make-a-cap...
For Iron Man it's not quite the same because it's a suit but it's just as impressive. Since Iron Man 2 there is no full suit worn by an actor. There are no legs and at this point there are barely even arms. There's a chest piece and open mask face piece and that's about it. http://movies.stackexchange.com/questions/2198/how-are-the-i...
In The Social Network there are a lot of scenes with the Winklevoss twins. Spoiler: They didn't use twin actors. They used two actors and CG'd the face of one onto the other body. No way in hell did you call this out on first viewing. (number 3) http://www.totalfilm.com/features/50-cgi-scenes-you-didn-t-n...