While atomic swap let you have control over your coin, it's not viable option for trader who aim for small profit due to fee of on-chain transaction.
It has to depend on the coin pairs. BTC has the most expensive transaction fee from the coins supported by xlitewallet. The fees for the other coins are cheaper and should be manageable for any trader.
I agree, but trader usually uses BTC, ETH or stablecoins (where some of them uses BTC/ETH network) to trade altcoin.