If you take the time to actually learn then a manual transmission can do a whole lot better in heavy snow or mud conditions than a similarly equipped automatic. Computers are getting really good at controlling things, but they're still not really up there with an experienced human driver when it comes to 'controlling the out of control' while slipping around on a hillside.
However, if you're the kind of person who thinks 'I have four wheel drive, and it will always save the day...' then it really doesn't matter a whole lot.
But the biggest factor to learning to drive stick and keeping up on it? Well that means you can drive stick.
It is one of those things in life, along with knowing how to haul and backup with a trailer, which really doesn't matter all that much until life throws it your way.
Need to borrow a friend's car? If you don't know how to drive stick, then you're rather SOL if it is a manual transmission.
Yup. When I was living in a mountainous region with lots of snow and bad roads, I was thankful I was driving an old POS F-150 that had a four-speed manual. Using your brakes on ice and snow is not the greatest idea, being able to lock your transmission in third and have that hold you back to a safe speed as you go down a twisty hill is a whole lot better.
Now if we could just get rid of ABS brakes, so the wheels would lock up properly, I'd be happy. It's dangerous as hell if you are used to the old-style and have to drive a newer model. Your instincts are all wrong.