But when people are talking about coin flipping, they are talking about real profit, not trade PnL. If your overhead to get into a trade is more expensive than the PnL on that trade, your consistent ability to make that trade is not a good thing, and that negative should be counted against your win rate wrt things like the efficient market hypothesis.

Again, I actually don't have strong opinions about coin flipping and trading being equivalent (and I think Virtu is likely a bad place to have that conversation vs a hedge fund because its not really an investment firm its an execution one) but I think claiming trading PnL refutes it is wrong.