Really? Didn't see that in FAQ or here. Still, nope. It was my 2nd post so it was impossible for me to add either of these. (And it was actually a reply to your post ^^)
The only place it was mentioned was in a profile post by Tony-chan. It was also added to the http://forum.novelupdates.com/threads/findings-about-money.20783/ thread, though that one is easy to miss.
Its so that you can have a full month of tony teasing parth.. can only be done with nakama power tho.
psst go earn some and sell yourself after losing it all in blackjack desu im willing to have more sla....."cough" enthusiastic gamblers desu~