Both tokens you were trying to withdraw (BAT and USDT) are ERC20 tokens. This means that that don't have their own blockchain and are running on ethereum blockchain.
Sending an ERC20 token is even more expensive than sending Ethereum. Because the transaction needs to spend more gas due to larger size of data.
I just visited Bilaxy to check networks they support for withdrawing USDT. They support Tron network as well.
For withdrawing USDT on Tron network, you must select "TRC20" option.
The fee they get for withdrawing USDT on Tron network is 2 USDT and the minimum withdrawal amount is 5 USDT.