IMO, it's always better to see a full arena but obviously with both casual and proper fans. Empty seats kinda make the whole ambiance less enjoyable, at least from a viewer's POV. Usually it's proper supps who make the noise and casuals who fill the stadium. It's like that anyway in France. And I do think that casual fans are needed... they are the one who buy the most expensive tickets !
Are US stadiums organized with Kops by the way ?
And why no Libertadores ? Not good enough ?
Or is about federation stuff ?