Away from the cities, the highly skilled driver is safer with a manual. The lesser skilled are probably safer with an automatic.
Not too many will put up with a manual in the cities, though.
My Beetle has it, but it seems to be a fourth-generation VW thing, as my (several years older) Cabriolet does not.
One thing that confused me a bit about your story is that grandma apparently had the car in gear without having the brake pedal depressed, only the parking brake. That’s a situation one should never be in. Newer automatics will not generally shift out of Park without the brake pedal depressed, as a safety feature.
I believe they added this feature based on a few well publicized complaints that vehicles accelerated “on their own” after being shifted into gear. Chances are, people just did the same thing your grandmother did, but blamed it on the car instead of themselves.
Frankly, if she had trouble making sure her feet were on the right pedals, adding a third one is probably not going to help. Accidentaly hitting the brake instead of the clutch can cause a major accident too.
I had an Old Datsun 510 that could be started in any gear (it was a 5 speed manual)
I had a 57 Chevy truck you could start in drive or reverse (automatic)
It all depends on who made the car and what fetured they included.
IIRC a Zil I got to test drive while in Russia did not have the saftey feature, Then again it was a Zil 
I had an Old Datsun 510 that could be started in any gear (it was a 5 speed manual)
I had a 57 Chevy truck you could start in drive or reverse (automatic)
It all depends on who made the car and what fetured they included.
IIRC a Zil I got to test drive while in Russia did not have the saftey feature, Then again it was a Zil