> Trading cards are ponzi schemes too. From an entertainment point of view, they are created for the purpose of being fun to trade.

No, not really. You're confusing the concept of intrinsic vs perceived value, and completely ignoring the concept of utility.

People who buy cards for fun do it because it's fun, just like we could spend money to rent a sports car, go on a vacation, or drive around a test track. The monetary value of a hotel say from last month is zero, but that does not make hotels any type of fraud.

What would represent a Ponzi scheme would be, say, advertising Beany Babies as a safe and guaranteed investment to attract speculators, sell them Beany Babies for a hefty markup, and proceed to leave them holding the bag.