I think nowadays the answer is usually that you have to know how to do both. At least, if you are the kind of person who appreciates the old fashioned way of doing things, but you don't want to get left behind by new technology, it means you must learn and practice both ways. One is for yourself and the other for the outside world.

I think it is important for children to learn to write with a pen or pencil and to write in cursive. It's good for the fine motor skills and it connects them with a tradition that is unbroken for thousands of year. It establishes them within the continuity of civilization. Whatever other skills they need to learn to navigate the world today will have to be learned on top of that.