Though a page by page mark might usually be enough for readers, the LastWord bookmark is a reading tool for those who need serious specificity. Beyond just marking off that last page that readers were on, the unique bookmark has a placeholder that points to individual words, allowing readers to leave their book and be sure that they return to precisely the same thought when they return.
It might seem silly, but there are plenty of common situations in which the LastWord bookmark would come in handy. When reading through a dense textbook or academic paper, missing out on a paragraph of information can be killer, but reading over the same blocks of text can be headache-inducing to say the least, so the LastWord is a good solution. Plot-driven books also punish readers for accidentally skipping ahead, as that can end up spoiling crucial points in the narrative.