I read "Lead" as the element Pb...a metal in the context of "magnet" because I've never really thought about those free ebooks as "lead magnets" since I'm not tuned in to marketing jargon despite having a bit of exposure to the literature of growth hacking over the years.

Which brings me to my point that the market for your product includes segments, e.g. content creators, who don't tie the term "lead magnet" to the concept. Those people need a bit of education about your project because the value proposition isn't entirely clear until the term is tied to the concept. Helping an author put on the marketing hat is necessary before making it easy to take their marketing hat off and get back to writing has value.

Good luck.