As long as i know, there is no network more secured then ERC20 now, but it is too expensive. Why erc20 moee secure ? Because it has been hacked so mny times and TRC20 never getting hacked so no improvement in security. Erc20 also has many nodes keeping the security of it, TRC20 more less.
You mean that erc20 is hacked many times and trc20 has never been hacked or you wanted to say another way around ? I think both of them are secure therefore you see lots of USDT being transferred through TRC20.