This information is about a week old....and Fauci is talking about 50% of the transmission being from asymptomatic?
You are incorrect. People with no symptoms could be asymptomatic, or pre-symptomatic. Your assumption that they will never show symptoms is a wrong assumption.
It appears people have the highest viral load right before symptoms show themselves. This means they have no symptoms to trace at the time of transmission, but can be traced after the fact.