The context is tradeable tokens that are built on top of cryptocurrency platforms like Ethereum.
I rounded down a bit to compensate for some of the lower volume cryptocurrencies and any potential issues with market cap that it might not be reporting correctly.
You can get to $30 billion just by taking the current total number of Bitcoin + Ether outstanding and multiplying by their respective token prices. Admittedly both numbers are inflated some amount due to tokens being unknowingly lost/destroyed, but I think we're still in the ballpark of $30B.
There is also a few hundred million (possibly low single digit billions) of venture capital in startups based on cryptocurrencies.