Picked the second option. It's a minor motivation.
I probably have one of the more unique primary reasons for open carrying: it enables me to carry larger handguns. Probably after that is the ease of access. Then there's the "because I can, and I'll be damned if you're going to make me hide my gun" factor. Somewhere below that lies the deterrent factor.
I have a standing challenge to anyone to find a comfortable way to conceal my handgun without the use of an outer garment.