Eurovision goes bossanova

Someone in Greece has had the (old) idea of making bossanova versions in Brazil of the Eurovision songs and the result is very laid back and rather pleasant. But why didn't they make these songs in Portuguese then to make them sound more authentic? Some versions work very well - Ding a dong, Waterloo, Volare, L'oiseau et l'enfant and Where are you to name some - while this also makes it obvious