How is this technique different to the traditional note taking?

In terms of genre, traditional note-taking always be noted with phrases and paragraphs, however sketch-noting includes pictures and different marks. Sometime, it will be hard to describe something literally, sketch-noting offers a clear way to transfer the meanings.
As for style, sketch-noting is casual,although there are three layouts to make sketch seems better, but people will draw differently. Compared with it, traditional note-taking will be much more formal, and it seems much more similar.
People who noting with sketch always have extra ability than the other note takers . For example, they need to be familiar with how to visualize words with graphics, so that their sketch-noting can be much more practical and usable.

How does this visual approach facilitate communication of your ideas? Conversely, how does it prevent it?

This is an era of visualisation, a increasing number of people prefer to read pictures rather than paragraphs. Sketch provides us an opportunity to describe things with graphics, which makes note more interesting.
In addition, sketch-noting can submit sentimental meanings directly. We use simple lines to show emotions and body languages. Meanwhile, it is easy to illustrate trend, timeline and fluctuation using sketch-noting.
However, sketch-noting needs me too draw quickly and clearly, otherwise it comes to be confusing and remind people something else.

Personal challenges as a sketchnoter.

As for me, there are two main challenges.on the one hand, I have to think logically and organize an outline in my min before taking sketch-noting. On the another hand, when I was listening to a speech, the TED one, it was hard for me to draw at the sometime, because I was thinking about the content, layout and details all the time.

The following photos are my sketch-noting.