When running a dApp decentralized application from the Ethereum Blockchain, it usually performs its own token form. Trust Augur's REP number or Bancor's BNT number.
ERC-20 is a standard created after the arrival of ETH, which shows how notes work and how to keep a regular record of those exchanges between notes on the Ethereum network.
As noted in Above, ETH was the initial trademark of Ethereum Alt tokens, which means it was developed before the ERC-20 standard.
The WETH explanation is that it is possible to replace ETH with other ERC-20 numbers in decentralized stages such as the Radar Relay. As decentralized processes work on Ethereum, each customer must have a similarly standardized design for each symbol they exchange, as they use cost-effective contracts to work directly with their customers. This guarantees that the notes do not lose the meaning of the whole direction in the explanation. I liked the design of this project and it is easy to access the website. Language support is also good.