Writers of haiku in English often employ em-dashes and ellipses, and less frequently colons and semicolons to indicate a pause. This practice is a result of English not having an equivalent of the kireji or "cutting word." (See the Haiku Society of America's note on its haiku definition here.) I think the use of em-dashes in haiku can also be overdone, I know I've found myself using them a little too often.
The lesson here is--everything in moderation--including the use of em-dashes!