Most photographers are not qualified to supply press ready CMYK either as tiffs or pdf. Those that are, and you know who you are, will need to be able to make a valid pdf-x1a for delivery to various publications. The advantage is that everything is locked down. The disadvantage is that everything is locked down, and if something needs to be changed, it has to come back to you. There are many options in the Distiller dialogs that can trip you up. Even the defaults are not acceptable for me as they automatically use jpeg compression, which can, in rare instances, cause problems. While pubs are more likely to request pdf-x1a, higher end printers printing sheetfed may prefer to have your Quark or InDesign document for when things go wrong - and they will, sooner or later.