Same argument can be made for tobacco salesmen, drug dealers etc. If people pay money for something then they MUST derive some benefit from it... I find that assumption questionable.
Other things I could mention: multi-level marketing, snake oil sellers e.g. homeopathy astrology etc.
I find the assumption that every casino and gambling company in existence provides no benefit, of any kind, to any of their customers....extremely questionable.
Other things I could mention: multi-level marketing, snake oil sellers e.g. homeopathy astrology etc.