There are times when many people seem to think it is, or at least in a visual medium like film and animation it is. I see it in Fanboy-Perspective's defense of Batman V Superman and Clark's lack of dialogue in it.
But there are times when I do feel telling is better then showing. Especially if you're someone who wants less Origin Stories in Superhero movies, what you basically want is to be told not shown. Likewise if you don't like overuse of Flashbacks, you want to be told not shown. And I'm annoyed how many fans feel that dead Robin easter egg means some DCEU film HAS to flashback to when that happened, how about we just leave that to the imagination for a change?
If you are the opposite of me on the issue of if movies should be longer or shorter, or if you feel the same. Sometimes telling is shorter and sometimes showing is shorter, it depends on what you're trying to communicate.
But the thing about any medium that has acting as one of it's story telling tools. Is what you can do by showing how a character tells something, and how others react while listening. When trying to understand Shakespeare, it's import to know that Elizabeth audiences would cared more about what they heard then what they saw.
In the 70s TV Miniseries Jesus of Nazareth, there are many things I don't like about it (mainly the White Washing) but also things I think it did well. One of it's highlights was showing Jesus tell the parable of the Prodigal Son to a room full of people, it was a far better choice then cutting to a dramatization of it.
I enjoyed Suicide Squad, but yes it is a flawed movie. One of it's highlight is El Diablo telling his backstory in the bar scene. I feel that could have maybe been improved by not having any flashbacks, but just having him tell the story.
If a movie is ever made of John Devil. I do not want any "Flashbacks" or whatever you might call a Dramatization of the stories Henri Belcamp tells about his adventures in Australia and on St Helena. One reason is because none of those stories are entirely true, and the audience of a movie tends to assume anything we see play out must have happened.
But also because I want to see Henri Belcamp be an Orator. I want to show how he plays his audience and how they are suckered in by it. Same thing if a movie was made out of The Vampire Countess, another Paul Feval novel translated into English by Brian Stableford.
So no, what I'm saying is we don't need to see everything, it sometimes works to just tell us.