I suppose if a Cameroon or Costa Rica (or USA) got that far, they would enjoy one last chance to go home on a high-ish note.
But Argentina or the Netherlands won't possibly want to be there. Just to beat (while getting fouled like crazy) eleven Brazilians on heavy anti-depressant meds.
“Why do they have the third place game? Do any of the teams want it?”
Sure; it is the equivalent of a bronze medal in the Olympics.