It holds $7.55b worth of cryptocurrency in its smart contracts. Not in a bank account, or on a centralized exchange like Coinbase, but in lines of code running on the Ethereum blockchain.
Normally on a CEX like Coinbase, they own the supply of tokens and they collect all the trading fees. But on a DEX, anyone can add liquidity and earn a share of the trading fees. On Sushi for example, 0.25% of every trade goes to the liquidity providers.
But today, you can create a new token and add the necessary liquidity to Uniswap, and your token is immediately available to anyone in the world. No gatekeeper approval required.