In Skyfall movie Bond fights an assassin and captures a casino token in the assassin's stuff which he later cashes out. Clearly the token is used as payment for the assassination. Note that assassination fare is likely very high so it's a token that yields some really huge sum of money, not a regular casino token that yields several dozen to several hundred USD (or equivalent thereof).
Why is it done this way? What's the significance of using a casino token except that it leads Bond to the casino and that lets the plot progress?