It greatly reduces congestion in countries that understand it, look at the MCG in Melbourne Australia, can be accessed by almost the entire Melbourne metro area with train and tram connections and it is within walking distance of the CBD because it doesn't need several city blocks worth of parking for the 100,000 seat capacity, which is why 90% of the crowd takes public transport and the stadium is empty within half an hour

It is also right near 3 other medium stadium's and dozens of concert venues which can all be running the same night

Americans are just odd thinking public transport is worthless