Here's why:
* "Who dat?" is a very specific phrase used in New Orleans, particularly during Saints games. It's a call and response chant, showing team spirit and excitement.
* French doesn't have a similar phrase with the same cultural significance.
Possible ways to express the sentiment:
* "C'est qui ça ?" (Who is that?) - This is a literal translation, but it doesn't convey the same energy as "Who dat?".
* "Allez les Saints !" (Go Saints!) - This is a more appropriate way to express excitement for the team, similar to "Who dat?"
* "Qui est-ce ?" (Who is it?) - This is another option, but it's less energetic than "C'est qui ça?".
Ultimately, you'll have to choose the phrase that best conveys the meaning you want to express.