I don't think the point was to get visitors directly from those links, but to hope that the referer URLs were ending up in some kind of publicly visible page (e

I don't think the point was to get visitors directly from those links, but to hope that the referer URLs were ending up in some kind of publicly visible page (e.g. the logs directory of the HTTP website being exposed), have those pages indexed by search engines, and get a URL reputation boost from those inbound links.