If you're referring to these tickets, they're for mobile users who does daily rolls only. Perhaps due to billing process being handled differently by ios appstore and google playstore, the daily 100 yen roll on DMM are increased to 120 yen. As a result, you're given 4 ticket pieces, which 20 pieces will allow you to convert into 1 full ticket to roll.

DMM and Nutaku differences-ticketpiece.png