The trailer is on the DVD and I just watched it again. At first I thought it was a little too corny for an Eastwood movie but the more I watched it, I realized that it was probably appropriate.
It definitely makes it clear to everyone that this is going to be a downright comedy. Anyone seeing the trailer first would not be surprised by the kind of movie it is once they get to the theater and that may have been one of their goals in doing it this way.
At first I thought there was some kind of mistake or technical difficulty on the DVD. There's a complete blank screen while this couple talks about going to see a movie. Then they begin to talk about Eastwood in the various scenarios of the film (as scenes begin).....fighting, falling in love, being beat up by a woman (Ma - Ruth Gordon), confessing his affairs with an orangutan, etc.
My guess is that people who saw this trailer, without any prior knowledge that Eastwood was going to make this movie, were probably a little stunned and maybe couldn't believe he was going to do this comedy.
It's cute if you like corny and I think that's probably what they were going for.