Lionel Messi is one of the most recognisable footballers in the world, and tchau is the everyday Portuguese word for bye, so the phrase works instantly for Brazilian and Portuguese-speaking football fans even without extra context. As a user-generated meme clip, it has circulated on soundboards and in short football edits where a goodbye doubles as a joke about a transfer, a defeat or a player being outplayed. Its staying power comes from that simplicity: the name carries the football reference, and the farewell carries the punchline.