Apple shares are worth money because they entitle one to a share of ownership and voting rights in a company that engages in real wealth production, and would be worth lots even if they reinvested all their dividends like Amazon.
The same cannot be said of these kittens... that this obvious point even needs to be stated is just sad.
He's not suggesting the markets are imaginary, simply suggesting that there isn't a backing asset to stabilize them. Sure people buy counter-strike skins right now but there is very little reason to believe that the current version of counter-strike in which these skins exist will be popular in perpetuity. At some point people will move on from the game, maybe even to the next version of counter-strike... at which point those assets values will decrease significantly. Just like people moved on from beanie babies, and just like they'll move on from crypto kitties.
To suggest that these things are anything other that highly speculative is intellectually dishonest at best, gambling at worst.
I think the point is one can imagine someone believing their $117k cat breeding lots of kittens that they can manage to sell for ETH (and/or later exchanged to USD), netting them a profit after some time.
The same cannot be said of these kittens... that this obvious point even needs to be stated is just sad.