Many years ago there was a story told of a couple vacationing in Miami and while driving through town the wife suddenly told her husband to roll up his window as she rolled up hers. As the husband turned his crank he asked why and the wife replied, “you don’t want these people to know we don’t have airconditioning do you?”
That was a very funny tale 50 years ago.
Very funny 
No offense, but I’ve worked on COUNTLESS vehicles that had a cabin air filters AND mildew
And believe me, those cabin air filters were replaced frequently. So the mildew had absolutely nothing to do with poor maintenance
It was to a large degree because the cars weren’t programmed with an afterblow function, and/or the feature wasn’t yet activated . . . you need a factory-level scan tool to do that
I’m sure you’re correct. I didn’t mean to suggest that all vehicles equipped with a cabin filter are immune to mildew.
However, I think it’s also correct to state that dirty water evaporates more slowly than clean water, and so dirty vents will retain the moisture for a longer period of time and thus give mildew a greater chance to grow.
For what it’s worth, I have had several vehicles over the years, none of them are equipped with an afterblow feature, and the ones without cabin filters get dirty vents and are more prone to smelling bad if you leave the air conditioner on until you turn the car off. The ones with cabin filters have gone more than 100k miles without any mildew problems, and you can also see that the vents are very clean.
My oldest Granddaughter was 3 years old when I took her for a short drive in my RX-7. She had never seen window winders and spent the entire drive rolling her window up and down, amazed by the unfamiliar ‘technology’.
I agree with “researcher” and, besides, it keeps the condensate off of your garage floor…! 
The benefit is reducing mildew growth and associated evil smells by allowing condensation that forms on the evaporator (air chiller) to dry prior to shut off - a logical idea. If your AC doesn’t small bad, no worries. If it smells bad maybe you should be doing it.
I often do this if the vehicle will be sitting for a day or more, especially if its really humid. We have a sienna we started to get a musty smell, or at least a hint of one. Once I started running the blower for a bit it seems to be gone now. Now keep in mind that this van might get used on a Sunday and sit in the garage until the following weekend or longer. I also do this on the truck I am assigned to at work before the weekend. It started getting musty after it sat a few days.
Fwiw when we had our Prius V I never did this and sometimes it would sit a while after running the ac and I never noticed a musty smell from the vents.
Some vehicles are more prone to odors, I remember GM had a kit in the 90s for some vehicles that was called an “after blow” module. It would run the fan for so long after the car was shut off after the ac had been on. This was to deal with cars that were getting musty ducts.
Same response from a friend’s grandson when riding in his old Corvette.
If the magnetic compressor clutch was not disengaged when the engine was shut off, the current of the magnetic coil draw from the battery would leave you needing jumper cables the next time you drove the car.
I’m pretty sure that that all compressor clutches need 12 volts to the clutch coil to engage the clutch.
You might be right, but I was thinking of the AC compressor load on the crankshaft if the AC clutch was engaged. That would cause increased current draw by the starter motor, which already draws a lot of current turning the crankshaft over. I wasn’t thinking of the clutch engagement current draw.
Whew. My last post to this thread was a year-and-a-half ago, and I had to go back and reread the thread in its entirety to refresh my memory! I had no memory of the thread until I reread it.