People do puzzles for a wide variety of reasons. In some cases, they are just trying to pass the time and they are looking for something convenient that will help them to do so. That isn’t to say, however, that people only do puzzles because they are bored. Some people love puzzles so much that they will continue to do them, even if they have something else to do.
You also need to consider the wide variety of puzzles that are available. Some people like jigsaw puzzles, which typically means they will be sitting at the table for hours on end trying to find a piece that will fit into a particular place in the puzzle.