With so much note taking apps nowadays, I can't understand why does anyone still write notes with pen and paper. You need to bring the notepad, book or that paper to retrieve that information, and most of the time you don't have it in hand. While my phone almost always reachable and you carry when you go out. For those still like to do handwriting, there's many app does that and they can even convert it to text notes.
So, if you still write notes with pen and paper, why?
At home I take notes on the computer. Timestamps, instant sync across devices, whatever editor I like to use, et cetera. If I get a random call and someone starts talking at me, I'll settle for scribbling on a fast food receipt if it is close to hand. I use my phone sometimes, but I generally take notes when I'm on a phone call.
When I'm at an in-person meeting with a client, pen and paper is the best option because it conveys some degree of respect. People still seem to be put off by people pulling out a laptop and typing during an emotionally charged meeting. If I pull out my cellphone and start poking at it in a professional setting, people don't think that I'm listening or taking notes. They think that I'm bored.
Seconded on the respect comment. It may not be fair, but I think people using their laptops in meetings are distracted by the myriad notifications constantly bombarding us, checking email, or otherwise not staying engaged. Harder to be present when your device keeps clamoring for your attention.