The majority of ‘Cryptocurrencies’ are not native to their own blockchains.
Cryptocurrencies, such as USDC, USDT, and PAX, among others, were issued on a several blockchains and when using them, the transaction fees are always paid in the native token of that specific blockchain. This transaction fee, is known as ‘gas.’
For example, in case you are trying to send USDT on the Ethereum blockchain, the gas will be paid in Ether (ETH), the native token of the blockchain.
This applies to all tokens on the Ethereum blockchain.
Instead, if you are trying to send USDC on Polygon, the gas will be paid in MATIC. If you find yourself needing the native token to perform a transaction from the DeFi wallet you can solve this buy buying the native token on your Blockchain.com account and sending it to your DeFi wallet or by receiving the native token on your DeFi Wallet directly.