Mini-Bibliobattle, a book-report activity in which students present and vote for their favorite books, has been reported to enhance learners' interest in reading and improve their presentation skills. This activity can be incorporated into ER, and students can present their books and bridge reading with speaking. However, the specific factors that distinguish Book-Champions from other participants in terms of reading and presentation styles remain unclear. A questionnaire survey revealed that winners were more likely to: 1) attract the audience’s attention, 2) speak fluently without hesitation, and 3) use gestures frequently. Follow-up interviews indicated that winners read their presenting books more carefully than other books, focusing on key highlights. Additionally, they selected books that personally interested them, allowed them to incorporate their own experiences, or had storylines that were easy for the audience to understand. These findings suggest that Mini-Bibliobattle encourages students to engage in more careful reading and deliver more captivating presentations.