To my way of thinking, pen and paper's real advantage comes from the bit of extra time it takes to use them. I can type nearly 100 words a minute. Most often, the thought that first comes to mind isn't usually the best one but it's typed and the writer's mind is already on the next thought to be typed. When you handwrite your ideas, your brain gets a little more time to ruminate on an idea without having to spit it out and rush on. With a little extra time to expound on an idea, a better version of it usually comes along and can save time during revisions. First thoughts are like first drafts. They need revisions.
This much I agree with; I often find writing things out longhand helps. I spent several years writing everything in a notebook with a fountain pen and only typing up afterwards. You don't type ahead of your thoughts, and you can't go back and endlessly edit a previous paragraph.
I write on the computer a lot more often now, just for convenience's sake (and because I no longer live in the neighborhood where I used to walk over to a coffeeshop after work with pen and paper), but I still write longhand often. Especially with short stories.
As I've said before, where I find technology most invaluable in writing is for notes. Since I keep all my notes in Evernote, I can jot something new down on my phone wherever I am (even if I'm in line at the movies, where it would be hard to open a notebook and jot something down in pen), or pop it open on my computer if I have an idea during the work day, or access my Evernote notebook on my iPad and prop it up next to the notebook or laptop while I write. I may still like my fountain pen, but you can take my digital notebook when you pry it from my cold, dead hands.