What this does is change the rules to Itadaki Street 3. Here's the difference:
Default Rule : When you have the goal amount, you win if you go to the bank castle.
Itadaki Street 3 rule : Even if you land on the bank castle with the goal amount, you don't necessarily win. If there's another player that has more than you (meaning they have the goal amount AND some more), they win.
VERY useful if someone's 1 space away from the castle and you're 20 spaces away and you're both going for the finish.