Merchandising or merch as some people like to call it, the bits and bobs, cups for some bookmarks for most-which makes no sense to me since most of the people doing it are only selling ebooks-but whatever. Then there the pens and even necklaces. Yet I'm not even sure I want to get business cards, so as far as spending money on bookmarks when I'm only selling ebooks, spending money on merchandise doesn't make sense to me.
Argument for is to hand out the 'goodies' to your readers who will hopefully be reminded of just how awesome you are every time they look at said bit or bob. Will your pen float into the hand of a new reader who will look you up and discover your awesomeness? Will someone see your fan using/displaying your bit or bob and comment then get to hear your fan chatter on about how awesome you are? Perhaps it will inspire loyalty or at the very least some fond memory that will carry over to sales. Because here's the issue, unless it translates into sales or unless you have money to burn there are so many other ways you could and should be spending your money.
Argument against is basic, unless it translates into sales you should be focusing your time and attention to writing books and not checks for something that will likely not be used or tossed the next time a clear away is done. Because the problem with merchandise most of it is disposable as in having little value to the owner because it was a gift and because most of the items are inexpensive. I used to go to a used bookstore and there was a cup of bookmarks for free with information on books and authors like so many giveaway and I have to tell you even though I used them until they got lost or bent out of shape and I looked at them and thought 'oh that looks interesting' I never once looked for an author or a book that I saw on the free bookmark. As I went there often looking for new books to read why didn't I ever look for books by the authors, because it was free I didn't place value on it.
It's because of that that I don't see the real value in merchandising. Am I saying never, hell no but I'm saying at this time as I debate spending money to advertise on Goodreads and shudder over it, I don't think it's worth it.