We all know that selling points and/or miles by participants of reward programs is illegal.
However, the question is why it is legal for an airline or a hotel chain to sell miles/points? By doing this, a company sells some sort of certificates with no guarantee that those could be redeemed for a specific flight or a hotel stay. Also, the companies that are selling such products (i.e., miles and points) have the rights of 1) terminating the reward program that would nullify the value of the points purchased and/or 2) change the redemption options.
If the risks of purchasing miles/points are not properly disclosed to the customers, such an activity would constitute a consumer fraud.
Note that currently none of the conventional retailers are involved in selling certificates for future redemption at an unknown rate. Why this is allowed for airlines and hotel chains? The same questions would be for purchases of airline miles by credit card companies.