The differnce is that there is another regulation which reads:

12.060 Use of chips and tokens.
1. Chips and tokens are solely representatives of value which evidence a debt owed to their
custodian by the licensee that issued them and are not the property of anyone other than that
licensee.

unlike your check, their is a Nevada regulation which says that the chip is the property of the casino. So while a chip that has value (is evidence of a debt) may not be taken by the casino unless it pays its debt ---- later in 12.060 we are told that a licensee must "Promptly redeem its own chips and tokens from its patrons by cash or check drawn on anaccount of the licensee;". However in this case were the chip no longer has any value the casino isn't required to pay the value, but that doesn't change the fact that the chip is the property of the casino.