If we read between the lines, Christopher Nolan is stating the Marvel films aren't real movies.
Nolan, director of The Dark Knight Trilogy, revealed an interesting piece of information regarding Man of Steel, of which he was an executive producer.
Nolan told the Guardian that Warner Bros. asked for a post-credit scene in Man of Steel that was similar in vein to the Marvel movies.
Nolan's response was a big no to that:
When the studio asked if Snyder would add a comedy coda ending, in the style of Marvel, Nolan’s reply was “A real movie wouldn’t do that.”
As fans know, Marvel includes post-credit scenes in their movies to entice audiences for what is to come, such as Nick Fury setting up references to the Avengers in Iron Man.
Now, is using a post-credit scene such a bad thing?
It's possible Nolan means the post-credit scene info should be included in the movie, as it could be argued it's almost a lazy way of promoting something, albeit even if fans think they are pretty cool. Perhaps Nolan is just taking a jab at Marvel or even being a bit hoity toity, but he may have a point in that if something is as important to include at the end of the movie in its own separate feature that it should be somehow included into the overall movie (such as the Joker card at the end of Batman Begins instead of used as a post-credit scene).
Of course, this begs the question of what a Man of Steel post-credit scene would have featured. At the time, did Zack Snyder and Warner Bros. even know Batman was going to be featured in the next movie? Or if Man of Steel hit that magic billion dollar box office number, would they have gone with a straight Superman sequel?
Marvel from the get-go was building to Avengers. Was WB building to Justice League with Man of Steel?