Great stadium, very few spectators - after all the visiting team  does not match attractiveness of Sporting or FC Porto - practically, Estadio da Luz is crowded only when those Primeira Liga giants are coming.

Whoever visited Lisbon and was driving a car from the airport into the direction of Cascais, is aware the two Lisbon rival stadiums are within just 4 km from each other. One may wonder what prevented both clubs from bulding and subsequently using and maintaining the shared venue - see the Milan, Rome and Genoa examples for some reference.