I could hedge it at the blackjack table too -- that doesn't make a blackjack hand a financial asset. I'm talking about whether the instrument itself is backed by something of inherent value.

You could buy a stock expecting asset appreciation, but the stock itself is a certificate of ownership in a business. Even a derivative of this, like options trading, is a contract to buy or sell or deliver said certificate of ownership in a business. Ultimately it is backed by something of tangible value.

"Predictions markets" are all of the mechanics of trading, but without any underlying value. It is literally gambling wearing Groucho glasses. The bet is simply for the sake of the bet.