It will be useless if they pay with USDT because basically USTD is using ETH network. You can see how fee that will be chargered if you send USDT in one wallet to USDT in another wallet.
This is the problem that we head, everytime a coin is increasing then the gas fee will increase as well. ETH will launch new system ETH 2.0 that can reduce its gas fee per one transaction, I think it will resolve for those who complain against gas fee.
Usdt is not only available on Ethereum network mate, usdt is also available on Tron network and it's gas fee is far more cheaper than even bitcoin itself so yes it makes lot of sense if the team can consider to send usdt instead of tokens right now, you need to do your own research, I'm shocked that someone don't know USDT is available on Tron