No middleman is needed, but who executes exchanges on the blockchain?
One detail: Ethereum mainnet went live in July 2015 and was one of the first public blockchains capable of running general-purpose smart contracts.
Smart contracts can’t read off-chain data themselves, so when they need external data such as exchange rates, it has to be brought on-chain through an oracle.
Remember this instead of memorizing a bunch of jargon. Don’t rush into placing an order just because everyone else is doing it.
Calling a smart contract on Ethereum requires $ETH to pay for gas. Current: 2026.45.

Whether to buy or not is up to you; I’m just documenting this.