Cryptocurrencies might use Ethereum (ETH) for gas fees instead of their own token or coin for several reasons:

1. Network Security and Stability:

- Ethereum's Proven Security: Ethereum is a well-established blockchain with a robust security infrastructure. By leveraging Ethereum for gas fees, a project can benefit from its security without having to build and maintain their own equivalent.

- Established Network: Ethereum's network is already widely used and tested, reducing the risk of vulnerabilities or attacks that might be more common on a newer or less established blockchain.

2. Interoperability and Ecosystem Integration:

- Wide Adoption: Ethereum has a large and active user base, and using ETH for gas fees allows easier integration with other Ethereum-based applications and services. This interoperability can enhance the utility and accessibility of the new cryptocurrency.

- Developer Tools: The Ethereum ecosystem offers a rich set of tools and resources for developers, making it easier to create, deploy, and maintain decentralized applications (dApps) and smart contracts.

3. Economic Reasons:

- Market Liquidity: ETH is one of the most liquid cryptocurrencies, meaning it's easy to buy, sell, and trade. This liquidity can be beneficial for users who need to acquire gas for transactions.

- Stability: Relative to many newer or smaller tokens, ETH tends to have lower volatility. This can make transaction costs more predictable for users.

4. User Experience:

- Familiarity: Many users are already familiar with ETH and how to use it for gas fees. This reduces the learning curve and potential friction for new users who might otherwise need to learn about a new token just to pay for transaction fees.

- Infrastructure: Wallets, exchanges, and other infrastructure components typically support ETH, making it easier for users to manage and transact.

5. Technical Simplicity:

- Focus on Core Features: By using ETH for gas fees, developers can focus on building the core features of their own token. $ETH