You’re right that there is a fine line between preparedness and paranoia. That’s a balance each of us must find and it is not a one-size fits all answer. Both terms are subjective.
That said, relying on any intruders retreating doesn’t seem like a safe strategy. You don’t know the intent, experience or state of mind of the intruders. If they are desperate, used to being around gunshots, or whacked out of their mind on something, then they may not retreat. If you assume they will then you’re left at an extreme disadvantage. Does that mean you need a 30mm Phalanx in your driveway? No. But to recommend a single 3-round magazine is equally dumb.
So that vid is either staged, was too conveniantly recorded or some Mask Police stalker got lucky. Either way just more stupid society rearing its ugly head. I don't even find this crap funny anymore. Must be getting old and crabby(er).