Ethereum was the first network where anyone could issue their own token, and ERC20 is the set of rules for doing it. Hence how widespread it is: exchanges, wallets and services support it by default.
How it differs from TRC20 in practice
In price and predictability. The Ethereum fee depends not on the amount but on how busy the network is at that particular minute: sending ten dollars and sending ten thousand cost the same. In a quiet hour that is a few dollars, at peak noticeably more.
From this follows a rule of choice: small amounts are cheaper to send over TRON, large ones go wherever the recipient accepts them, because on a transfer of several thousand the difference in fees stops mattering.
What not to do
Send ERC20 tokens to an address on another network. An Ethereum address begins with 0x and looks identical to addresses on BNB Smart Chain and several other networks. Your wallet will allow the transfer, and the funds will end up on a network the recipient does not serve.
When paying extra for Ethereum makes sense
When the recipient accepts this network only, as many foreign services and some smart contracts do. And when the amount is large enough: a five dollar fee on a hundred dollar transfer is five percent, on a ten thousand dollar transfer it is hundredths of a percent.
How to avoid overpaying
The Ethereum fee changes several times over during a day. Nights and weekends are usually cheaper than the European working day. Wallets show the current price before you send and let you pick a speed: "slow" and "fast" differ both in price and in confirmation time.
If a transfer is stuck on a low fee, it is not lost: the network keeps it in the queue and will process it sooner or later. You can speed it up by resending with the same nonce and a higher fee, an option most wallets offer.
Read more: How to withdraw USDT without losing money on the network fee