Hi Lauren,
To be honest we don't enable 'attachment link' often, in fact, a quick check shows it's only been enabled for 20 out of c.2600 published articles.
I administer and manage customer satisfaction surveys in my organisation and we like to create a 'You said, we did' type of newsletter each month to let our customers know we're listening and acting on feedback. The newsletter is in a word document which we attach to an article. This article is signposted to our customers in the survey email invitation we send, the survey end note (i.e. "thanks for completing this survey, find out how we've acted on your feedback") and we also have an announcement banner on our service portal plugging the article.
In this scenario, having an article body doesn't really add much value and would result in an extra click because all it would say is something like "download the latest customer satisfaction newsletter". We've made sure that the short description is informative in case a customer performs a search on the service portal and the article is returned in the search results.
One limitation of 'attachment link' I've noticed is that you can't use the article permalink or the URL otherwise the article will open instead of downloading the file!
