Argent is a smart contract wallet which is the reason we can provide better security than any other wallet out there.
This security happens on-chain and therefore consumes gas for example to check whether an address is trusted, verifying guardian signatures etc. features like payment in any ERC-20 also consume gas. This is similar to multi-sig wallets.
Ethereum gas price is volatile and often high and this make this gas overhead much more impactful.
If you need to use Ethereum mainnet for smaller and more frequent transactions, it would be better to choose an EOA wallet.
If you want to benefit from Argent wallet security, it is worth to explore Starknet ecosystem where the gas fees are lower instead of Ethereum mainnet.