Calculating profit with USD is indeed easier than calculating profit if we trade COIN pair BTC / ETH / BNB. That is why more people trade with USD pairs than with other COIN pairs. Yet if we trade with other coin pairs such as BTC, ETH or BNB we can get double profits.
You're right, calculate our coins better use USDT or stable coins than top coins.
But there are trader that want to get double profit when market grow up, use top coins such as BTC , ETH and BNB.
It depends on your comfortable.
If you prefer in USDT or stable coins, do it.
OP said trading strategy ,profit is not on USD, sometimes I did.