It becomes significant if a crazy acts on it. I don’t think they believe it themselves for the most part.
He raises his hand as he says "the murderers will be killed"; this action is interpreted as a signal to implement a plot.
The black beard: September 11 is referred to as "Black Tuesday" on the jihadi forums.
The call to convert: We all know that this precedes an attack. I hate to say it, but heads up for another 9/11.