Yay finally a Taiko Goofs that is not a Dummy Version leak! This bug, possibly stemming from a not-so-optimal algorithm in checking, could get you way more Don Points than you should have got!
A quick recap about Don Points for those who don't play AC0 (or don't have AC0 to play): Normally each credit will give you 100 Don Points (DPs hereafter), and if this is your first play of the day, week and/or month, there will be an additional 50, 100 and/or 300 DPs. For instance, the first-ever credit you play after a Rewards Shop version change should net you 550 DPs, and then any subsequent credits on the same day should only give you 100 DPs.
To get the bug, you will have to start other credits on different AC0 cabinets before the first credit is finished and the Don Points tallied. All the credits that were started like this will all get the first-play bonuses. In the video's experiment, the Taiwanese Donders tried the bug with three cabinets in two arcade centers and they end up getting 1650 DPs (550+550+550) instead of the "correct" 750, verifying the theory.
However please let it be known that by exploiting this cheat you would be hogging multiple cabinets at once which is very bad arcade manners. Please be considerate about your fellow Donders.