It's all about what Bannon does next
First of all, there's no doubt that Bannon was fired in reality. Surely he would have loved to stick around the White House.
Usually, people are given the opportunity to resign. That's what Anthony Scaramucci did.
There are currently conflicting reports about whether Bannon was fired or resigned. The New York Times reports that he resigned on August 7 and they've just been waiting to make the announcement. It's tough to believe that was kept under wraps but just moments ago reporter Sara Carter says she spoke to Bannon himself and he said he quit.
That would be a good sign for Trump.
A bad sign would be if Bannon forced them to fire him. Then he could position himself as a martyr of a White House that was taken over by 'globalists'. He's rumored to be heading back to Breitbart which he could use as a platform to attack the administration, or at least his rivals within it. Those kids of attacks would further weaken Trump and could divide his voters.
In the thick of trading today, the semantics probably won't matter but if he goes quietly and 'voluntarily' it says something about how he will treat the administration going forward.
Meanwhile, Washington Post reporter Robert Costa says Bannon has told associates in recent days that if he leaves, the Trump White House will be "Democrats, bankers, and hawks." Bannon predicted Trump would rebel. That's also a clue into how the far right will begin to brand the Trump White House.