[bombcar]

They're a liability of the airline, and they're an asset of the customer, but they are not an investment, because they can only go down in value, not up.

Same as gift cards.

[Scoundreller]

Sometimes the dollar price of a flight goes up but the points price stays the same = points went up.

[breser]

That you can make money through arbitrage is not the definition of a security. See my link above.