USDT is the most used stablecoin in the cryptocurrency market, there is no doubt about that, but it doesn't mean that Tron is the most secure and successful blockchain right now. Besides, the fees for transacting USDT on Tron network aren't low, so you can't say it has low fees which might make it the best among the competition. I don't understand how you can compare a centralized cryptocurrency and chain with decentralized ones such as the Bitcoin blockchain.
Tron might be good to some extent, but saying it is number one would be a bit too much, in my opinion. There are a lot of L2s these days in the market, and each one of them offer low transaction fees and quick transaction confirmation times, I'm sure some of the new ones are even better than Tron.
even most of L2s are already having dirt cheap fee right now which make me thinks that even if TRON offer no fee for stablecoin transfer as proposed by justin sun already it makes no difference whatsoever.
the fee thing becomes irrelevant already.
here is the fee from ETH's L2 zksync for sending ERC20, the fee is really low that I think it's cheaper that TRON
so yeah I agree, this metric to determine TRON as best is invalid and holds no proof.