Where the hell do you live? Afghanistan, Iran, Detroit, City of God???? Where that you'd easily know that such "serious self defense" situations is about to go down? You make a mistake and you'll be the one going to jail, even for brandishing.
You're not the only one with gun in America. I have guns in my bathrooms and shit because I don't want to get home invaded while taking a shit. But I'm not pulling out my gun out over every thing in the streets. Brandishing it w/o just cause can mean lost of CCW and perhaps felony conviction, ending up with me having to get rid of all of my guns and never own one again unless I do a Gordon Liddy move. Then there's lost of job and all that shit that comes with a felony conviction w/GUN involved.
This is why we train and fight, in order to drop some fool or at least take a few hits w/o shriveling up and then go for the gun, maybe not even...and just duke it out.