It's the whims of emotion - in the moment a person says it it can be quite sincere, as that's their genuine mood in that instance, but later on the mood passes

It's the whims of emotion - in the moment a person says it it can be quite sincere, as that's their genuine mood in that instance, but later on the mood passes and the effort involved in arranging something outweighs the desire. In that sense it does communicate something: I like and have enjoyed your company in this moment. Flippant of course, but not too dastardly.