Whatever the term, if the coins can be exchanged back into a real currency or goods, they have real value, and as such they’re as good cash.

Wikipedia:

Pachinko balls won from games cannot be exchanged directly for money in the parlor, nor can they be removed from the premises or exchanged with other parlors. However, they can be legally traded to the parlor for so-called “special prize” tokens (tokushu keihin (特殊景品) [ja]), which can in turn be “sold” for cash to a separate vendor off-premises.