I'm no expert on this stuff and don't pretend to be, just offering my humble opinion from my experiences, but yeah basically what you said regarding shootings is a part of it.
Perfectly possible to have a totally clean shoot with a lazer sighted Bushmaster loaded with handloaded reversed jacketed killbuzz whackamitic bullets. Just as possible to go to prison for a slightly grey shoot with a .22 bolt action. But simple is best and the less you give the other side talk about (or the DA to ponder) the better. People say "We'll I'll just explain I was using "x" because of "Y-Z" or "Show me a case where somebody was convicted because of "x". Well thats not the way it works, it's more subtle...
You won't be saying much (hopefully) when Police are forming there first impression of you on the scene of a shooting, other factors may influence their on the spot decisions and subsequent reports. You won't have much of a chance to explain anything to a DA as he's mulling over reports (or newspaper articles) filled with buzz words like "Assault Weapon" or "high capacity" deciding whether to file charges or not, and you definitly won't be in chambers where all kinds of things are discussed that would never come out in open court. My favorite example of this was when I was trying to get man who molested a 13 year old girl 21 years and had to spend 20 minutes defending how the girl and her mother! dressed to the Judge, even the guys attorney was rolling his eyes trying to change the subject:banghead:
On to more nice (and far more likely) advantages. In Missouri where I live laws on transporting a handgun are really vague and hard to understand. Maybe it should not be but frankly every police officer I know would look at a blued 6" Model 14 just a bit different than a Tec-9 if you were in that "Honest mistake" grey area. Same as above yeah you could go to jail on either but ones gonna make them look at you a lot harder than the other should you make some technical bobble. May be wrong but I'm the same way with knives on my Parole cases. Find one of my cases with a folding "work" knife thats a bit too long I tell him to leave it at home, find the same guy toting a butterfly knife around town he's in trouble.
I think frankly it's also a bit of a help in other peoples perception of you. Carrying a "PC" gun out to car your is less likely to get neighbors talking about you (or even other range members). Easier for folks on the fence gun control wise in your circle (family, friends, employers) to accept and frankly even when at gun shows or new shops I think most tend to treat me a bit better when I ask about seeing a Model 15 target revolver than when I ask to see a Glock.
Nothing against semi-autos I own some and support the right of the people to own them (even with nasty hi-caps and flash suppresors). But yeah as a whole I think life could be simpler being thought of as "Ol Blueduck with his harmless traditional six-shooters" than as "That guy who lives down the road with the arsenal of semi-automatic weapons". YMMV
Best,